Gottlieb System 1 Control Board / MPU Capacitor type???

[JRK1971]

Hi guys,
Im repairing the acid damage on my countdown.

The service manual mentions the capacitors on the control board/ cpu are 0.01 micro farad 100V, but doesn't mention type of cap - eg
tantalum, greencap etc. See attached schematic and picture of control board.

Does anybody know what replacment to use - I have Greencaps @ 0.01 micro farad but aren't sure if they will suit the circuit.

Thanks, regards John

[Homepin]

The original blue one is a polyester type (IE = greencap) but for that application a disc ceramic would do equally well.

So your greencaps would be perfect.

It is NOT a polarised type so you shouldn't use a tantalum or electrolytic type.

[JRK1971]

Thanks Homepin - you have saved my bacon. 

[beaky]

The original blue one is a polyester type (IE = greencap) but for that application a disc ceramic would do equally well.

So your greencaps would be perfect.

It is NOT a polarised type so you shouldn't use a tantalum or electrolytic type.

+1 on that.
Make sure you remove every sign of corrosion and replace any component that has corrosion on the legs.
I also remove the solder out of any via that has been affected also and reflow them with solder.

[JRK1971]

Thanks again Homepin and thanks beaky for the confirmation. 

Three hours last night yielded this so far… Six replaced resistors and a lot of cleaning/ desoldering crystallised solder joints. Reckon I have another 20 hours to go; this is tedious work & I don’t want to wreck the board.
There was acid right under both removed IC’s in the red section, was a bloody pain to get any solder flowing to remove the IC’s legs after I cut the silicon off.
I forgot how much fun  removing crystalised solder joints was.

I can see why these boards are uneconomical to repair if you have to pay people. Upside is it keeps the game original and it plays original (I’ve got a pascal board, used it once and then repaired my orig – not that im knocking the pascal board, its great, I just prefer the original startup sequence and noises).

I’ll post a pic once Im done, Im gonna use some cct board lacquer after the repairs to seal the copper.

On another topic, have you guys ever replaced the copper fingers on the edge connectors  – if so, how? I’ve re-flowed mine, but I have to keep re-doing occasionally as the copper underneath is not great.

[beaky]

I tin them and then suck any excess solder off.
the connection is only as good as the highest points, I have received these boards with a thick coating of solder on the contacts many times but his only damages the pins in the edge connector housings.

on one board the copper was totally cactus on the contacts for the edge connector so i had to attach a piece of perf board that jaycar sell, the pitch is perfect.