The Aussie Pinball Arcade
Aussie Pinball Forums => Technical Matters => Pinball Repairs / Problems & Assistance => Topic started by: MartyJ on May 10, 2009, 03:56:15 PM
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Hi Guys,
I've got my powersupply rebuilt and are now getting correct voltages. I've done all ground mods for both powersupply and MPU (driver board out for time being)...Is setup on work bench with power section from cabinet (caps replaced, bridges tested etc..)...
I am not getting any display what so ever. From the PinRepair guide (still learning how to use logic probe correctly), but it would appear that CPU board is booting OK.
I tested voltages at pin 17 and is 60v...
I disconnected one and tried the recharge with a 9v battery and don't get anything out of the display. I tested the UDN6118 on this display and they seem to be OK...
Any suggestions would be appreciated!
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Do you know if the displays are supposed to be working? If possible, get hold of a known working display and hook it up to test.
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No. Not sure about any of them.
Machine was sold 'as is', not tested and this was how I requested it. (as a project for me)...Was fully explained and understood by me that machine NOT tested or powered on prior to purchase..I was happy to roll the dice with a BH and thus far (touches wood) has worked out very nicely with almost all components/parts checking out fine....
At this stage I'm leaning towards the fact that perhaps all displays are shot. Just looking for confirmation on how to test this..From reading the old 9v (and have tried 12v from new cap) and I'm not getting those funky red lines to heat up. This indicates a problem AFAIK.
I guess its possible that they are all gassed out but I don't know enough about them to speculate..
Solid 60vDC to each connector for displays too. Grounds buzz out fine on all too...
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Won't hurt too much to get some second-hand ones, I reckon.
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Won't hurt too much to get some second-hand ones, I reckon.
Agreed.
I'm having a look around for one in the mean time....
Not sure if you can get LED replacements for Gottliebs either.....I was a big fan of the PinScore I put on my PF.
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My alligator lead was down to 1 strand so that has been fixed and elements within at least 4/5 displays are glowing....Sooo, rather than take a shotgun method to replacing parts I will try to nut it out.
I have some schematics but I need to print them out on A3 but don't have those facilities with me....From reading U5 RIOT is a suspect...
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Would be strange for all displays to be dead so i think your on the right track
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My alligator lead was down to 1 strand so that has been fixed and elements within at least 4/5 displays are glowing....Sooo, rather than take a shotgun method to replacing parts I will try to nut it out.
I have some schematics but I need to print them out on A3 but don't have those facilities with me....From reading U5 RIOT is a suspect...
Ah, the old one-strand alligator lead will always cause problems.
From what I have heard on this forum, the RIOT chips are often suspect.
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U5 done. Nil value.
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My Cpu also seems to be booting as per clays guide but i also get nothing so hopefully i get something once the brand new cpu arrives?
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IF I was getting junk or partial's, at least I would know where to start.
Voltages across pin 34 of RIOTS appears to be OK as well.
@@^
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I would be pretty sure that most of your displays are Ok.. If you have the lines glowing and they are straight lines and not pulsating when you added your 9 volts to the two outer pins then there probably Ok. I would seriusly doubt that all displays would be faulty.. These FUTABA displays far outweighed the Bally/Stern displays of the same era for longgeviti...
Dean
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I would be pretty sure that most of your displays are Ok.. If you have the lines glowing and they are straight lines and not pulsating when you added your 9 volts to the two outer pins then there probably Ok. I would seriusly doubt that all displays would be faulty.. These FUTABA displays far outweighed the Bally/Stern displays of the same era for longgeviti...
Dean
Thanks Dean,
Initially when I was not getting anything, I thought it may be displays....Faulty alligator clip later and that side sorted. Still no displays at all.
Welcome to System 80!
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Sounds like the CPU is not booting
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Have you checked the filiment voltage?
5v AC across pins 13 and 3 of A14 P1??
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I am tending to agree now, although initially I thought it was OK...
I've got my Chinese "Faithful" brand logic probe....
According to the 3 lines of documentation 1(red) led = high, 0(grn) led=low and pulse(yellow)=pulse. No audio on this one...
I will start again via the Pinrepair guides for the CPU....Although my first play with the logic probe I thought was OK...
For example on the upper leg of the crystal, I get all three lights - so if I am understanding it correctly it is going high, low, high, low, high, low (pulsing)???
I would much prefer one with the lcd screen....
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Marty, you mention in your previous posts that you have cheked the 60 volts and gound to the displays.. Can you confirm please that you have the filiment voltage of 5 volts AC and the +5 Volts DC to the displays, before we decide it is the CPU
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Marty, you mention in your previous posts that you have cheked the 60 volts and gound to the displays.. Can you confirm please that you have the filiment voltage of 5 volts AC and the +5 Volts DC to the displays, before we decide it is the CPU
Have you checked the filiment voltage?
5v AC across pins 13 and 3 of A14 P1??
I will double check now. Previously I used the green earth on the display (DMM on DC) on pin 19, and pin 17 which I got 59.? and 60.?v...
Re the 5v AC - this should be pins 15 & 16 if I am reading the schematic correctly?
Noob had is on too....A14-P1? You may have to direct me to this as I couldn't find it....Playfields are out at moment too...
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Not sure what way you are reading the pins on the display.
Looking at the face of the display (glass tube) the plug that plugs into it is nombered right to left, very left pin 21, very right pin 1.
So you should have 5 Volts AC between pins 13 and 3. 5 volts DC between pins 12 and 4. These are pins of the plug not the display glass
Edit: wrong way around Very right pin is 1 and left is 21.. Have corrected in post above.
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On P1 display plug I have the following (if the pins are correct)
Pin 19 - GND...Tested on all and buzzing out.
Pin 17 - 60.1v DC
Pin 16 - nothing (on AC)
Pin 15 - nothing (on AC)
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I will check your way...I was going by pin 19 being green and buzzing to earth and on top side of pin (plastic) is labelled 19 (being far left) ...with otherside being 1... !@#
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I will check your way...I was going by pin 19 being green and buzzing to earth and on top side of pin (plastic) is labelled 19 (being far left) ...with otherside being 1... !@#
Sorry Marty, please re-read my post above... very right is pin 1
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I will check your way...I was going by pin 19 being green and buzzing to earth and on top side of pin (plastic) is labelled 19 (being far left) ...with otherside being 1... !@#
Sorry Marty, please re-read my post above... very right is pin 1
OK...I'm getting tired so I will pull the pin shortly...I apologise if I'm not doing this correctly...
I've run gnd off the COM on the PSU. On pin 12 (DC) I'm getting 4.9v. On pin 04 (DC) I'm getting 0.0v. On pin 3 (AC) I'm getting 0.0v. On pin 13 (AC) I'm getting 0.0v.
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I will check your way...I was going by pin 19 being green and buzzing to earth and on top side of pin (plastic) is labelled 19 (being far left) ...with otherside being 1... !@#
Sorry Marty, please re-read my post above... very right is pin 1
OK...I'm getting tired so I will pull the pin shortly...I apologise if I'm not doing this correctly...
I've run gnd off the COM on the PSU. On pin 12 (DC) I'm getting 4.9v. On pin 04 (DC) I'm getting 0.0v. On pin 3 (AC) I'm getting 0.0v. On pin 13 (AC) I'm getting 0.0v.
No need to apologise Marty.
Measure between Pins 3 and 13 for the AC voltage i.e meter on AC volts put one lead on pin 3 and the other on pin 13, should have a reading of 5 VAC
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I will check your way...I was going by pin 19 being green and buzzing to earth and on top side of pin (plastic) is labelled 19 (being far left) ...with otherside being 1... !@#
Sorry Marty, please re-read my post above... very right is pin 1
OK...I'm getting tired so I will pull the pin shortly...I apologise if I'm not doing this correctly...
I've run gnd off the COM on the PSU. On pin 12 (DC) I'm getting 4.9v. On pin 04 (DC) I'm getting 0.0v. On pin 3 (AC) I'm getting 0.0v. On pin 13 (AC) I'm getting 0.0v.
No need to apologise Marty.
Measure between Pins 3 and 13 for the AC voltage i.e meter on AC volts put one lead on pin 3 and the other on pin 13, should have a reading of 5 VAC
OK, DMM between pins 3 and 13 on AC. 0.0v
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All that is plugged in too is the connector from power unit (from lower cab floor) to power supply, power supply to CPU, J3 (which powers from PSU to displays/playfield) and the two from the CPU to the displays. Is there another from the power unit which should plug in?
There is A12-J4 (red) but no corresponding red plug from the loom from backbox (although one is missing label)..
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I will check your way...I was going by pin 19 being green and buzzing to earth and on top side of pin (plastic) is labelled 19 (being far left) ...with otherside being 1... !@#
Sorry Marty, please re-read my post above... very right is pin 1
OK...I'm getting tired so I will pull the pin shortly...I apologise if I'm not doing this correctly...
I've run gnd off the COM on the PSU. On pin 12 (DC) I'm getting 4.9v. On pin 04 (DC) I'm getting 0.0v. On pin 3 (AC) I'm getting 0.0v. On pin 13 (AC) I'm getting 0.0v.
No need to apologise Marty.
Measure between Pins 3 and 13 for the AC voltage i.e meter on AC volts put one lead on pin 3 and the other on pin 13, should have a reading of 5 VAC
OK, DMM between pins 3 and 13 on AC. 0.0v
Ok, if thats correct then thats a problem. You need this for the displays
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I recall reading about the voltages going from the powersupply board, back to transformers then to displays? Not sure if this is correct or a dreamt it....Is there a connection I'm missing as that may make sense?
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All that is plugged in too is the connector from power unit (from lower cab floor) to power supply, power supply to CPU, J3 (which powers from PSU to displays/playfield) and the two from the CPU to the displays. Is there another from the power unit which should plug in?
There is A12-J4 (red) but no corresponding red plug from the loom from backbox (although one is missing label)..
Yes the AC is fed from A12-J4
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OK, so at the moment, A12-J4 is NOT plugged in. There is a red connector (fits) coming from backbox without a label. Its the only red one...
So should they be connected together....(just cautious don't want to plug wrong shit in and really make a mess)
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OK, so at the moment, A12-J4 is NOT plugged in. There is a red connector (fits) coming from backbox without a label. Its the only red one...
So should they be connected together....(just cautious don't want to plug wrong shit in and really make a mess)
Yes it needs to be plugged in...however, site unseen I cannot comment on if thats the correct plug to plug it into...but if it fits it most likley is!
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Some progress...
Not smoke or bang.
P1 is showing roughly in the middle what looks to be a no. 6 (perhaps with a 1 locked on) and P3 is showing a 0.
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Some progress...
Not smoke or bang.
P1 is showing roughly in the middle what looks to be a no. 6 (perhaps with a 1 locked on) and P3 is showing a 0.
Sounds good, I must go for today. Try swapping Player 1 and 3 displays and see what happens. Good visual way to tell if the processor is running is to see if the displays cycle from high score to date to last score played. If you leave it on should cycle ever 5 to 10 seconds or so.
We will get there in the end *%*
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Some progress...
Not smoke or bang.
P1 is showing roughly in the middle what looks to be a no. 6 (perhaps with a 1 locked on) and P3 is showing a 0.
Sounds good, I must go for today. Try swapping Player 1 and 3 displays and see what happens. Good visual way to tell if the processor is running is to see if the displays cycle from high score to date to last score played. If you leave it on should cycle ever 5 to 10 seconds or so.
We will get there in the end *%*
Thanks for the help thus far. Two steps forward....
Well at least I know now the CPU is not booting....
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Thanks again Dean,
Now armed with a new Fluke so I can trust DMM readings a bit more. I emailed Clay too about that some DMM's may give readings on his Sys 80 guide (MPS-U45's) that they are bad, but if the DMM has less than 2.000v on the diode test will continue to give bad readings. Not bad transistors, just DMM not enough grunt to give his readings! Hopefully may save someone else a headache down the track..
I've been going through the http://www.geocities.com/kirbseepe/repairCPU.html guide as well.
From the start, my Z26 (pin 12) is definately not giving 5v at all. Somewhere to start at least!
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The logic probe (I think) is starting to become handy.
It also appears that my IRQ is stuck LOW (pin 4 U1).
I've replaced U4 and U5 RIOTS....
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DOes that have something to do with the game rom not working from memory?
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DOes that have something to do with the game rom not working from memory?
Not 100% sure as yet. I'm chasing my tail a bit as problems are somewhat intermittant. For example, this morning, IRQ was stuck LOW and had funny displays on screens.
Tonight, IRQ is getting stuck HIGH.
According to Clay's guide, it may be issues with U2/U3 game ROMs.
I'm hoping for someone who may be able to guide me in this area.
Reset appears to be functioning correctly, I've replaced crystal and Z2 & Z3 just to be sure. U4 & U5 also changed. U1, U4, U5 & U6 all appear to be getting clock signal too.
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Well i didnt get mine goig but when i replaced the game rom u2 it fixed the irg maybe try removing the chip and reseating it since its intermitant?
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Not an option.
On my breed of Sys80 board both U2 & U3 are NOT socketed!...
Looking at other options at this stage...Are they expensive to get?
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U5 reseated again.
Out of about 10 powerups, IRQ is constantly getting stuck high.
I am happy to replace U2/U3 if required. Is there anything I can check before pin 4 on U1 if it is causing issues with the IRQ?
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Marty - I have not spent enough time on system 80 MPUs to assist here, so I'm a little "out of my depth" - But - If you need ROMs and you want to "dig deeper" with the board - Try Ed at GPE ;
http://www.greatplainselectronics.com/proddetail.asp?prod=120-102
I'm thinking of getting a Quickscan - Just for a "play", as I have quite a few Sys80 boards I need to fix. Clay gets dirty in his guide;
http://www.pinrepair.com/sys80/index3.htm#testrom
ROMS
http://www.greatplainselectronics.com/proddetail.asp?prod=140-101
I might have an untested board you can use for testing.
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Hey Marty
The rom for rock cost me around $70 with postage etc. Mine has an adapter so i cant even lend you mine for a test.
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Marty - I have not spent enough time on system 80 MPUs to assist here, so I'm a little "out of my depth" - But - If you need ROMs and you want to "dig deeper" with the board - Try Ed at GPE ;
http://www.greatplainselectronics.com/proddetail.asp?prod=120-102
I'm thinking of getting a Quickscan - Just for a "play", as I have quite a few Sys80 boards I need to fix. Clay gets dirty in his guide;
http://www.pinrepair.com/sys80/index3.htm#testrom
ROMS
http://www.greatplainselectronics.com/proddetail.asp?prod=140-101
I might have an untested board you can use for testing.
Thanks Nino,
I've sent Ed an email for a couple more spare parts. He is a System 80 guru. He is out of stock of the Quickscan's, but I'll wait for his response to see what he recommends. I am thinking it would be a good purchase either way. (hmm, maybe a HH too one day!)..
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If the tests are done correctly then it is a good chance that U2 or U3 is bad. Also try it with the game prom removed. and test the IRQ then to ensure this is not dragging it down.
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If the tests are done correctly then it is a good chance that U2 or U3 is bad. Also try it with the game prom removed. and test the IRQ then to ensure this is not dragging it down.
I will do this now and report back. I think between me learning how the logic probe works and my nice new shiny DMM I believe I've done everything right as per Clay's guide.
I've emailed Ed again - asking very very nicely if he has a QuickScan tucked away somewhere (shop listed sold out) of his QuickScan's....Just in case I get a HH or another Sys80 type game...Plus probably handy for someone locally to have one in case others get into trouble!
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Yep, still high with PROM1 removed.
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If the tests are done correctly then it is a good chance that U2 or U3 is bad. Also try it with the game prom removed. and test the IRQ then to ensure this is not dragging it down.
I will do this now and report back. I think between me learning how the logic probe works and my nice new shiny DMM I believe I've done everything right as per Clay's guide.
I've emailed Ed again - asking very very nicely if he has a QuickScan tucked away somewhere (shop listed sold out) of his QuickScan's....Just in case I get a HH or another Sys80 type game...Plus probably handy for someone locally to have one in case others get into trouble!
I was going to buy one just for that very reason. I have several system80s in the pipeline and I wanted to have a Quickscan handy for others that may run into problems in the future.
Let me know how you go - I might want one as well Marty.
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If the tests are done correctly then it is a good chance that U2 or U3 is bad. Also try it with the game prom removed. and test the IRQ then to ensure this is not dragging it down.
I will do this now and report back. I think between me learning how the logic probe works and my nice new shiny DMM I believe I've done everything right as per Clay's guide.
I've emailed Ed again - asking very very nicely if he has a QuickScan tucked away somewhere (shop listed sold out) of his QuickScan's....Just in case I get a HH or another Sys80 type game...Plus probably handy for someone locally to have one in case others get into trouble!
I was going to buy one just for that very reason. I have several system80s in the pipeline and I wanted to have a Quickscan handy for others that may run into problems in the future.
Let me know how you go - I might want one as well Marty.
Ed emailed me back. No luck. He is well and truely out of stock with the boards. He is hoping to start production again but no time frame unfortunately.
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Hey Marty My new CPU arrived today and all went well around $350 all up so if you get stuck its an easy option
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That will be an option but I'm not going to be beaten by the Sys80...Its a challenge! But because of Dave coming to the rescue with the driver board, worst case I can do it.
I'm waiting on a U2/U3 adaptor and I've ordered enough spares for the displays in case segments are out etc from GPE...
I desoldered them both cleanly tonight...I may redo U6 as well, just for completness.
IF from my reading and the magic of the logic probe, all things are pointing to those being the culprets
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Yeah i would have stuck at fixing this one myself if it was mine but being for someone else and having other better games waiting for this one to go i just bit the bullet *% BUt good luck with yours
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U6 replaced, PROM1 replaced, U2/U3 replaced.
IRQ still high.
@@^
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5101 replaced as well.
Now I'm really stuck!
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Not sure on the polarity of the IRQ for that cpu chip, but typically IRQ's are meant to be high, and only pulled low when controlled from the other chips onboard. (of course your cpu may be the opposite of everything else).
Regarding your AC measurments on pins 15/16 (0v) did you try measuring with both MM probes on 15 AND 16?
It looked like you might have measured from pin15-to-ground, and pin16-to-ground, which would probably measure 0v, misleading you.
Any chance of running your display board down to Mark's to plug into a known-working pin to be SURE your displays are ok?
I also find it odd that only 60V is mentioned on your displays, typically Vacuum displays require pos & neg volts, typically +/-50v upto +/-100v etc....
just my 2c #@#
MM.
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Not sure on the polarity of the IRQ for that cpu chip, but typically IRQ's are meant to be high, and only pulled low when controlled from the other chips onboard. (of course your cpu may be the opposite of everything else).
Regarding your AC measurments on pins 15/16 (0v) did you try measuring with both MM probes on 15 AND 16?
It looked like you might have measured from pin15-to-ground, and pin16-to-ground, which would probably measure 0v, misleading you.
Any chance of running your display board down to Mark's to plug into a known-working pin to be SURE your displays are ok?
I also find it odd that only 60V is mentioned on your displays, typically Vacuum displays require pos & neg volts, typically +/-50v upto +/-100v etc....
just my 2c #@#
MM.
Thanks MM,
I think I've got the display issue sorted. From everywhere I've read pin 4 of U1 (CPU) the IRQ should stay high for the first five seconds, then drop to pulse (at 3.5v I think).
Mine is stuck at 5v and not pulsing - hence the board not booting.
I have just about given up on this. Its nearly got me beat. I cannot work out what else can be causing issues with the IRQ.
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Don't let it beat you ^^^
IF you look at the schematic, what other chips/pins does the IRQ signal go to?
Obviously a pin is holding it 'stuck' high, your logic probe should find this.
If chips are socketed (or you socket them) you can bend 1 pin out, so it doesn't plug into the socket, and although the chip will be working you can now measure the pin itself to see if it's outgoing IRQ control to the cpu is 'stuck' or not.
You would test chip-by-chip until lifting one of the pins out of socket brings the IRQ on your cpu back to life....
Failing the pin-bend method, perhaps just lift out all chips that control the IRQ cpu pin, then replace the chips one at a time, you should see the irq 'blinking' (as you said) until plugging 1 chip back in kills it again...
Another option is that all the IRQ pins are ok, and in fact a shorted irq track on the board etc.
If you point me to a schematic/link i can help you test/prove things too.
MM.
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Marty - I'll have a read of the schematic and see what I can think of.
I have an untested SYS80 board here (from my Force II project), that you may borrow if it makes things easier.
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New CPU in, couple of this resolved but still IRQ high.
From reading the schematic, IRQ begins at pin 4 U1 (6502) goes via R1 & R2 to pin 16 TC1 then to pin 25 U4, U5 & U6.
Is there anything prior to U1 which has anything to do with IRQ?
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New CPU in, couple of this resolved but still IRQ high.
From reading the schematic, IRQ begins at pin 4 U1 (6502) goes via R1 & R2 to pin 16 TC1 then to pin 25 U4, U5 & U6. Is there anything prior to U1 which has anything to do with IRQ?
TO help you follow the 'flow' in the diagram, the IRQ signal is going INTO pin 4 on the the 6502cpu.
( maybe this will help you follow signals with your probe/MMeter).
IRQ (Interupt ReQuest) is a signal that comes from all the other chips into the main cpu.
IRQ will pull low to interupt the main cpu(6502) to process information in the chip that interupted the cpu..
It's a way for an external chip to say to the cpu "hey, i have fresh data for you, stop what your doing and process my data"
MM.
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New CPU in, couple of this resolved but still IRQ high.
From reading the schematic, IRQ begins at pin 4 U1 (6502) goes via R1 & R2 to pin 16 TC1 then to pin 25 U4, U5 & U6.
Is there anything prior to U1 which has anything to do with IRQ?
Check the 5V at R1 - maybe it is shorted keeping the signal high ?
Can you bend pin 4 (so it is out of circuit) and see if it stays High on the CPU leg, then check the socket (in circuit).
I'm going off a schematic for a SYS80b - but it sounds the same.
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Getting around 4.8/4.9v on both legs of R1.
Will report back re CPU.
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With pin 4 bent out, no signal on it at all.
High on socket (pin 4)
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I'm guessing if you pull ALL the chips out of sockets that are on the IRQ line, then put them back one at a time, you should find 1 chip will 'hold' the IRQ high, when it was previously blinking wiht the other chips.....tedious elimination.
With all chips out, the IRQ pin might still be held high by a pullup resistor anyway.
Also to note, powering the cpu card on bench might not show the IRQ correctly, you'll need to create some activity on the playfield so the PIA's etc start generating IRQ's...
Typically, a cpu board sitting on the bench powered up wont be pulsing IRQ's at all, maybe this is part of the prob misleading your readings??
If anyone can send me a schematic/link, i'm happy to look thru it.
MM.
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I'm using the full game power board to boot it, but no playfield load etc.
The TOP video (for BH) and Clay's guide show them being booted on a bench (similar setup to mine) and all documentation states that the IRQ (even with only CPU powered) should stay high for 5 sec, then drop once game boots (around 3.5v I think).
Link here:
http://www.pinrepair.com/sys80/bhcpu.gif
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Are you using your Logic Probe to test this or your multi meter as im sure this should be pulsing
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Dmm for voltages as per Nino's req.
You're correct as to it should be pulsing once booted (5 sec). Mine is stuck at 5v (high).
Yes to logic probe too.
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I'd be switching to the logic probe for this process - but before you do - R1 should measure 3K. Can you confirm ?
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2.985 firm on R1
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Close enough (ie within tolerance).
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I do have spare resistors if required.
Going back over the schematics I cannot see anything else (other than U4,5&6) which may be causing the problem. Then in turn it could be any other IC hanging off the RIOTs.
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I do have spare resistors if required.
Going back over the schematics I cannot see anything else (other than U4,5&6) which may be causing the problem. Then in turn it could be any other IC hanging off the RIOTs.
Process of elimination - remove all the ICs involved and install them one by one until the signal remains high.
Each hour you spend on the repair will be an hour closer to the solution and you will learn as you go along.
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I NEED a schematic ^&^ heheheheehe :lol :lol
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I NEED a schematic ^&^ heheheheehe :lol :lol
Its on the link 4 posts up. Not a fantastic one, but all thats around.
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Thanx got the schematic, silly me 'selective reading' again, so i missed it hehehe
Umm, looking back at the start of post, although you have 'no displays at all' does the pin powerup or do anything? can u play a game, and flippers, bumpers, rollovers work and make sound etc??
(sorry if i missed this before).
I'm thinking maybe the master clock (Z3-7404 & Z2-7474 into U1-6502) might be dead? which would mean no bootup therefore no IRQ 'flash' that you expect to see.
The 'E2' link might be open?
Of course if the game runs, then ignore this, obviously the master clock is ok into the cpu...
Also, U1-6502, pin 39, which is a cpu clock signal going out to all PIA's, i'd be looking around there too, in & out of that Z3 etc....
The only bummer is you'll need a Cro or frequency display on your MM to measure the presence of the clock signal, capable of reading say 2-4Mhz ?? ??
You *might* be lucky that your logic probe has an inbuilt frequency-divider and will show a blinking pattern....try it i guess.
Also look at U5 pin34 (reset) and see what levle it is held at, maybe chip is held in a reset state??
I'd also look at U5 pin15 (Z26 pin12), and see what that signal is doing, it looks like the 'slam switch' does something to the score driver, blanking it? or something...if it's held in a state, maybe U5 is simply locked out, hence no IRQ??
Hope this helps.
MM.
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DID you do the slam switch Mod Marty? It wont boot without this done?
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I'm not sure about a 'mod' but the label on Z26 input says "slam switch"...
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Marty, check my post on CRO's...i reckon this will be your next test-gear purchase #@#
http://aussiepinball.com/index.php?topic=1686.0 (http://aussiepinball.com/index.php?topic=1686.0)
MM.
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Here is the link to the slam switch mod with the board not connected to the machine it thinks the slam switch on the front door is open so it wont boot... http://www.pinrepair.com/sys80/index1.htm#slam
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Ahhh, might be just what MartyJ needs to know....nice !
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Thanks for help guys,
Yep, slam mod done
MM,
No playfield attached at present. Just backboard and power section. AFAIK this is fine, power supply rebuilt and connected to CPU. Without displays attached (shouldn't matter) can still monitor if CPU booting by probe on pin 4 U1.
Clock seems to be fine. On my cheapo logic probe, I'm getting 1 (high) 0 (low) and pulse all lit which I believe is pulse. This is on Z3 pin 6 and U1, U4,U5,U6 pin 39.
U2/U3 are new. I dont know where to read the clock on these and couldn't see on schematic.
From the pinrepair guide, the clock looks to be OK, same as RDY and Reset. Something is holding the IRQ high. I have not touched or looked at Z9/Z10 or Z7/Z8. These are about the only ones I havn't replaced. From the schematics (Z9) there should only be activity on 4,5,6,7 & 14 (gnd).
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Pin 34 on U5 held high.
Pin 15 U5 held low
Pin 12 Z26 held high
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U2/U3 proms don't need clocks.
I'd monitor cpu pin40 (reset) which will toggle during bootup. (proves cpu is booting).
if pin40 is stuck, this is also feeding the 3 PIA's they might all be held in reset mode....
Z7,8,9,10 are all to do with prom/address decoding for various size proms....shouldn't be a problem, as your problem seems to be earlier than all that....
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Pin 34 on U5 held high.
Correct !
Pin 15 U5 held low
Pin 12 Z26 held high
Is the mod in between these 2 pins? they should both be low on the schematic...
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Pin 34 on U5 held high.
Correct !
Pin 15 U5 held low
Pin 12 Z26 held high
Is the mod in between these 2 pins? they should both be low on the schematic...
AFAIK the mod doesn't touch U5. Pin 13 is the only one which buzzs out to where the mod is.....
Pin 40 on U1, with DMM 0.0 then jumps to around 4.5 to 4.8v and holds there.
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Pin 15 U5 held low
Pin 12 Z26 held high
AFAIK the mod doesn't touch U5. Pin 13 is the only one which buzzs out to where the mod is.....
Pin 40 on U1, with DMM 0.0 then jumps to around 4.5 to 4.8v and holds there.
Pin 40 should ALWAYS be 5V (or near enough) which means the cpu is NOT in reset, that's cool.
Re-Check :
Pin 15 U5 held low
Pin 12 Z26 held high.
The schematic shows they directly connect, if one is high so will the other, yet you see 2 different levels?
maybe a cracked track in between these 2 pins??
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Hmm,
Definately NO continuity between pin 12 Z26 and pin 15 U5. Might be an error in schematics as the track from pin 15 u5 pin 10 Z12.
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Hmm,
Definately NO continuity between pin 12 Z26 and pin 15 U5. Might be an error in schematics as the track from pin 15 u5 pin 10 Z12.
Marty,
Just checked on two (2) spare boards I have and Pin 15 of U5 goes to Pin 12 of Z26 on both. One was a System 80a and the other system 80b. This is as per the schematic. You sure your looking at the correct ICs. U5 is the middle of the three 40 pin 6532s abd Z26 is the bottom right hand IC.
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Definately NO continuity between pin 12 Z26 and pin 15 U5. Might be an error in schematics as the track from pin 15 u5 pin 10 Z12.
Very weird, as the schematic shows Z12-pin10 goes to Prom 2 addressing, pin21, via the E2 jumper link....
^&^
MM.
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Definately NO continuity between pin 12 Z26 and pin 15 U5. Might be an error in schematics as the track from pin 15 u5 pin 10 Z12.
Very weird, as the schematic shows Z12-pin10 goes to Prom 2 addressing, pin21, via the E2 jumper link....
^&^
MM.
Sorry guys, tested again. Wrong pin.
Trouble counting this morning ^&^
Continuity OK pin 15 U5 to pin 12 Z26.
U5 pin 15 is high
Z26 pin 12 is high
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I asked for some help with this one (few days ago) on RGP.
The following was posted by a fellow RGP'er Kerry:
"U5 Pin 15 is driven by inverter Z26. Z26 pin 13 should be high (+5V)
normally and go to near 0V when the slam switch is closed. Z26 pin 12
should be opposite (near 0V normally and go to +5V when slam switch
closed). Bottom line... make sure U5 PA7 (pin 15) is near 0V (I would
guess it should be about 0.2V). "
My pin 13 is low 0.01v and pin 12 is 5.014v
Slam mod is definately done (removed old one and redid again).
I replaced Z26 this morning, no difference. Assuming the above is correct, something weird going on (apart from me miscounting pins)
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Glad you found the right pins hehehe.
Your measurments on Z26 indicate the slam switch (or mod) must be stuck on.
When Slam-Switch activated :
Z26-13 = Lo.
Z26-12 = Hi, therefore U5-15 also Hi.
and so the opposite is true...
In normal operation (slam switch NOT activated) :
Z26-13 = Hi.
Z26-12 = Lo, therefore U5-15 also Lo.
I'd now be looking at your slam-mod, or the switch itself, shorted diode on it or damaged/bent switch ?? ??
MM.
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Switch isn't connected.....I'll remove the mod and see difference.
Also, from the schematics can you tell me how do I know if a pin should be high or low?
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In this case, Z26-13 is 'held' Hi by the R20 3k resistor upto +5v.
The Capacitor C30 is there for noise filtering, removing some spikes from the switch contacts etc.
So, the slam switch (or output from the mod) on (connector J5-10) will need to go to 0v to change the state of Z26.
Assuming you know that Z26 is in 'invertor' whatever appears on the input (pin13) will be the exact opposite on the output (pin12).
Other than that, you would only know what Hi/Lo signals to expect when you know what the pins do on the chip.
You'd need datasheets on the chips to learn which pins need to be Hi or Lo to do their job etc....
MM.
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With mod removed:
U5 pin 15=low
Z26 pin 12=low
Z26 pin 13=high
IRQ still locked at high, no pulse.
OK, I understand re the hi/lo signals. I thought this was something you were deciphering from the schematics... ^^^
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Ok, so from your recent post, the readings on Z26/U5 are now as expected......DAMMIT !!! :lol