Stern - Cosmic Princess

[Rossco]

Decided to pop down to Altronics to get some crimp pins and a crimper to start the solenoid board rebuild. I have ordered from Bony Beast but not sure when the bits will arrive so decided to get going right away.

I have done tree connector replacements (1, 2 & 3 in the image) ... but so far no change in the fault.

So, with a full resolder of the pins done, there are only a few more connectors to do before I start on a full replacement of the pins. So far there have been no signs of and/or burnt or otherwise faulty crimp pins so I hope that this replacement exercise fixes the problem, else I am not sure what to do next..

[Pintoxicated]

Have you actually pulled the board out of the machine and checked for cracked solder joints on the pins?  Not impossible that the header pins are the problem.

Whilst the crimp pins may not have looked damaged, I can assure you that after 30 years they are not like new and should be replaced.  Did you notice whether the old pins were flattened compared to the new ones you put in?

My guess is that once you remove that board and inspect the back of the header pins closely you will find cracked joints which may well be your problem.

[Retropin]

You can test the connection between driver board and solenoids very easily by attaching a wire to ground braid and then touching the metal tab of the transistor with the other end of your wire, this will run the transistor to ground.. do this on the kick out coil and see if it fires.. if it does then all well and good.. the path from transistor to coil seems fine. If it doesn't then the fault more than likely is elsewhere and could lie between the signal to fire ( from CPU) and the driver. Take note though that when you do the tab test it determines the very last stage between driver and coil and so your fault may be before this which is either a faulty IC or signal connector fault. what the guys here are saying is 100% correct and to completely eliminate the fault you really do have to do the laborious task of repining the connectors and then maybe some more... it could be the connectors and often this is the case... your signal to and from CPU are the irritating ones on the RHS which you haven't done yet.
you could also have a fault with a buffer chip.. or a PIA etc. But before we get complicated.. do the mechanics and then if no luck we venture further

[Rossco]

Yes - I took the solenoid board off some while ago and resoldered all the pins in the hope that would solve the problem. As that didn't work, I started replacing crimp pins and then shifted to replacing the header pins and replaced the long, brown one on the right hand side (see pic) this evening. The rest should go quite quickly as I am getting familiar with the process and there are less pins to deal with. Should have new header pins installed and the board back in the machine by tomorrow.

Crimp pins seemed "normal" albeit a bit tarnished, but not overly squashed.

How do you spot a cracked joint?

Have you actually pulled the board out of the machine and checked for cracked solder joints on the pins?  Not impossible that the header pins are the problem.

Whilst the crimp pins may not have looked damaged, I can assure you that after 30 years they are not like new and should be replaced.  Did you notice whether the old pins were flattened compared to the new ones you put in?

My guess is that once you remove that board and inspect the back of the header pins closely you will find cracked joints which may well be your problem.

[Pintoxicated]

A cracked or 'dry' joint is just that.  There will be a hairline crack in the solder itself or sometimes a bit of a hole.  Whilst they don't look to be anything nasty, they can and often do render that particular pin defective.

I keep coming back to the point earlier that the machine started working a for a few balls or games after you re-seated the connectors.  That is a very good symptom that the connector/s or header pins are your problem.  Gav is spot on and there could be other components that have failed but the first step is to rule out the connectors and pins as your problem.

[Rossco]

Bad news ...

After a day replacing all the header pins, I have just reinstalled the board and one solenoid fired and all the lights came on ... and stayed that way. So, worse off than before - and something must be shorting. Hopefully I haven't done any permanent damage. Have left it for now, and near impossible to check that things are right without a circuit diagram. 

[Pintoxicated]

Oh dear.

Maybe just double check that you haven't got any solder splash bridging across some header pins and that you put the right connectors back on the right way.  It is easy to misalign them sometimes.  There could be other issues obviously but just check the quick and easy things first.

[Rossco]

Thanks - will give it a go. It there likely to be damage to some other circuitry?

[Pintoxicated]

Hopefully not but it all depends on what actually happened.  If you turned the machine off pretty quickly hopefully it will be OK and there won't have been any damage to the solenoid or anything else.  Maybe check the fuses and make sure you didn't blow a fuse as well.

[Rossco]

I flew like a rocket to flick the OFF switch ... didn't smell any burning...

[Zedman]

Sounds like it's Time to do some checking before next power on. Maybe using a series test lamp jig or variac would be good to avoid further damage. Semiconductors are gonna be quicker at blowing than you getting to a switch.

[Rossco]

I think that is beyond my capability.

Sounds like it's Time to do some checking before next power on. Maybe using a series test lamp jig or variac would be good to avoid further damage. Semiconductors are gonna be quicker at blowing than you getting to a switch.

[Rossco]

My spares arrived from RTBB today so I have pulled out the board again to start checking it over. The pins and crimps look much better quality than those I got from Altronics

[ralph67]

Yes Check voltages on the rectifier board first with only J2 connected, then move forward after all readings are all correct.  good luck.

[ralph67]

OK - I have removed the apron and checked the switch under the ball and it seems to be working correctly... BUT the ball is not ejecting automatically. If I move the ball into the pin launcher then everything is fine and the system resets and the game goes normally. I tried the self test and the solenoids cycle through but the ball ejector does not work during the cycle. That could be the problem. The switch seems to be new and looks like it's been replaced recently..

Should I test the solenoid with an amp meter?

Also, one of the five drop targets does not drop when going through the test cycle - no sure if that is an issue as they work correctly during play?   
All should drop during the test cycle. i would check the transistor that drives the little target trip coil. Each target has one of these, plus the larger coil that resets the whole target bank,  Mine used to reset twice at the start of a ball sometimes, prob a common thing as My Cheetah and Quicksilver do the same thing sometimes. or could be a mis adjusted switch on that target. or could be a broken wire to the  Target trip coil

The manual tells you what transistor fires each solenoid.

I am not familiar with Cosmic Princess but it may be a part of the game that you start off with certain targets up and others down, once you hit the ones that are up then it gives you others to hit.

The apron is the steel cover at the bottom of the playfield, the ball launch solenoid and mech is under there.
Take the apron off, check the resistance of the solenoid with your multimeter, if it is under 3 ohms resistance its probably cooked, also check the driver transistor on the solenoid driver board on diode mode with your multimeter, the link I posted will tell you how to do that, compare it against others that you know are working ok.
A visual inspection of the transistor may reveal damage too.