Motordome (6803) No Sound

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kevlarnic
Posts: 4
Joined: Tue Feb 12, 2019 1:44 pm

Motordome (6803) No Sound

Postby kevlarnic » Tue Apr 30, 2019 5:02 pm

I bought a non working Motordome that may not have worked for years & was most likely bought at an auction several years ago.
Anyway , i brought it back to life with sound and all, and it worked pretty well minus the fact that it was inconsistent at startup.
(could take 6 or more tries to get it going)
2 weeks ago a short under the playfield caused havoc. I replaced the fried driver... & replaced both U7,U8 (PIA) and U1(6803) chips to try to solve my startup issue. Now my startup is great and consistent. Over the course of 6 weeks every single chip on the mainboard has been replaced.
At startup i get the 3 flashes from "Cheapsqueak" and 9 from the Mainboard. I get a good loud belltone when I press the Cheapsqueak test button.
I did a system manufacture reset (65) and then set the sound to (3) for all sounds.
I believe the soundcard works fine but for an unknown reason the mainboard doesn't initiate the sounboard's sound.
The schematic shows 2 chips (U1 6803 & U8 6821) that interact directly with Cheapsqueak. I have replaced both.. still no sound.
Any ideas? The pots are good and the electrolytic caps on Cheap have been replaced. If anyone knows what signals i should see at SJ1 connector or
other helpful information ..please oblige. I have no issues using an oscilloscope, probe, DMM or frequency generator if required.
BTW , I looked at the 6803 online repair guide http://www.pinrepair.com/6803/ which is very light on this subject..

kevlarnic
Posts: 4
Joined: Tue Feb 12, 2019 1:44 pm

Re: Motordome (6803) No Sound

Postby kevlarnic » Mon May 13, 2019 6:09 pm

I resolved my problem . Got my user manual schematics enlarged to poster size at Staples then wrote down all connection points between the Mainboard to Turbo Cheapsqueak. So connector CJ5 to SJ1 and where the Soundcard SJ1 goes to on the Mainboard to U1 (6803) & U8 (6821). Turns out i had no continuity
between SJ1-8 and CJ5-15. Ran a jumper and voila that annoying Motordome Revving motor, bells, chimes and effects are back..
** There are 4 other wires from SJ1 to the Mainboard not going to CJ5 but all were good.**

Guard
MAACA Collaborator
Posts: 224
Joined: Sun Jun 04, 2017 1:23 am
Location: Guelph

Re: Motordome (6803) No Sound

Postby Guard » Mon May 13, 2019 7:03 pm

I can't wait until I'm smart enough to understand what you people say... :FP:
PINS- Hit The Deck/ Buccaneer/Sure Shot/Fire Queen/ Volley/ Tee'd Off/ Rollergames/ Star Trip/ Flip Flop/ Combat/ Flash Gordon/ Capt.Card/Bluenote/ Space Shuttle/Strange Science/Card Whiz/ Genesis/Bally Circus / Bally Beat The Clock/ Spanish Eyes/ Outer Space/Bronco
Projects- Jolly Rodger/Stratoflite/Pat Hand/ Tri Zone
RIP- Sinbad/ Supersonic



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