(Topic ID: 145348)

PinBot Capacitors for Audio


By wombat

3 years ago



Topic Stats

  • 8 posts
  • 4 Pinsiders participating
  • Latest reply 3 years ago by wombat
  • Topic is favorited by 2 Pinsiders

You

Linked Games

#1 3 years ago

Need some information regarding the main board capacitors. I'm currently replacing all the capacitors on the sound board and now need to replace the electrolytic caps on the main board. I specifically purchased "audio" caps for my sound board. Should I purchase "audio" caps for the main board as well? It appears that C2 and C3 are related to the amplifier next to it on the top left side (I'm not sure if that amplifier even helps the audio due to it's location to the J15 header.) The capacitors that I'm concerned about are C24, C26 and C29. Should I purchase "audio" caps for these as well? Is there a big difference between audio caps and normal caps? Thanks in advance - I do appreciate it.

#2 3 years ago

There are no specific audio caps. The caps are all electrolytic. The orientation is axial or radial. The uf has to match. The voltage has to
be equal to or greater but not lower than what is on the original capacitor.

#3 3 years ago

Why do you think those caps need to be replaced?
Is the game exhibiting a failure of some kind?
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#4 3 years ago

It's the dreaded audio hum Chris. It was somewhat noticeable with the original power board. When I changed out the original power board with an x-pin board, it was much worse. Cleaner voltage is actually showing other problems with older boards.

#5 3 years ago

I see. It will be interesting to see what you find.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info

#7 3 years ago

I just fixed a Big Guns sound board with excessive hum... My first step since i don't work on these sound board much was to just shotgun all the electrolytic caps in the analogue area. Still bad, shotgun the two amps... still bad... ARGghh...

Got the schematic out and started poking around like i should have done in the first place. I figured out my hum was coming from the +12v supply ripple getting into the amp......

Turns out it was a completely open tantalum cap next to an amp leg that went across 12v and ground. I didnt have a tant in that value (10uF i think it was) so i popped in an electro cap and all was well. Typically tantalum caps ESR raise up to a critical point and they explode when they fail leaving a visual clue as to what is bad. This sucker looked fine, but was completely open across the legs.

You can use general purpose caps in these sound and power supply boards. Get nice 105c caps for things near heat sources. Nichicon, Nippon, Rubycon, Panasonic, are all known to make high quality electrolytic caps.

Andrew

#8 3 years ago

Much appreciated Andrew. This helps. I did purchase the newer amps (TDA2003A) just in case replacing the caps doesn't help. There are 2 amps on a PinBot sound board but only one has a tantalum cap next to an amp leg. I cant read schematics but I can test and replace most items. It's sort of like remolding a room in your house. I plan on taking the main board out to replace older parts but then see another possible thing to replace - and another order

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