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Post-"Ben Heck Mod" Issues

ColecoVision Ben Heck mod modification composite AV picture delay stray sprites

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#51 HeadcolorsTV OFFLINE  

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Posted Wed Jul 18, 2018 3:09 PM

...And it looks like I know the first thing I'll have to do/look at:

http://atariage.com/...-pcb/?p=2495360

#52 -^CrožBow^- OFFLINE  

-^CrožBow^-

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Posted Wed Jul 18, 2018 3:27 PM

Yes we mentioned this also in another thread not directly related to Colevisions, but the traces on these things are crazy thin and will melt with the solder quite easily. I use a temp controlled Hakko iron and won't go beyond 300 Celsius when working on the CV. The exception is anything on the ground plane or when replacing the ground straps to the RF shielding. I have to bump the iron to about 700 to get anywhere on the ground.



#53 HeadcolorsTV OFFLINE  

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Posted Wed Jul 18, 2018 8:13 PM

Hmm. The RF box tests fine but loses voltage right before the jack. I'm also getting 0v to the VRAM, 0v to/from L3, and 0v from U20. I'm trying to follow it back as far as I can to locate the problem.

#54 HeadcolorsTV OFFLINE  

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Posted Thu Jul 19, 2018 4:24 PM

SUCCESS. COMPLETE AND TOTAL SUCCESS.

God bless the wonderful m--f--ers at ColecoVisionZone for uploading the service manual. The troubleshooting flow charts are a lifesaver. In short: I found that the copper coil inductor L6 wasn't getting the 5v consistently; partially because of cold joints, partially because the power switch wasn't delivering the juice properly due to damaged via pads at the "on" position.

I had to:
- take the leads from one of the caps I replaced,
- bend them into a tiny loop with a stem to go through the via,
- solder those itty-bitty stems to a half-inch lead of insulated wire
- feed the wire leads up from the underside of the board so the loops sit where the lifted/damaged via pads were
- solder the wire leads to the next pad/trace (jumping, basically, as a proactive measure)
- push the pins of the switch back through the vias, making sure to get the "on" pins through the lead loops (now my makeshift via pads)
- re-solder, clean and test

5v to L6. 5v to U20. 5v to the VDP. 5v to the VRAM. 12v, 9v, and 5v to the respective composite tapping points in the RF. ...5v going from the mod to the yellow jack! I don't think I felt more anxious about anything I've ever tried to repair than that moment.

Hooked it up, turned it on. The game: Mr. Do!

Picture: perfect.
Audio: perfect.
Artifacts: 0.
Picture signal loss over time: none.

The voltage is now consistent and steady.

Score: decent (I played skill 1, lol)

I decided to have more fun/test the reliability of the power flow, so I put in a different game: Venture.

1. I didn't know until last night that you can actually "beat" Venture for the CV; once you fill the treasure chart, you just keep repeating level 9 over and over until you lose all your lives.

2. It feels good to experience and talk about the ColecoVision as a GAMER once again. That was really my endgame all along.





Also tagged with one or more of these keywords: ColecoVision, Ben Heck, mod, modification, composite, AV, picture delay, stray sprites

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