Hi, I'll not help you, but I'm searching for help. I've an Educator 64 too, without his monitor, but i've a pet 8032 monitor. Is possible make it works? Il Mer 12 Lug 2023, 18:04 Santo Nucifora <santo.nucifora_at_gmail.com> ha scritto: > HI Gerrit, > > The TDA1170 has been replaced just to make sure it was not that. I am > fairly sure that during troubleshooting a couple years back, the NE556 was > swapped and the original put back in but I should recheck that. You do > make a good point about the socket however. Maybe a quick replacement is > in order just in case. > > I've also replaced most of the caps. A couple of the NP caps I could not > get direct replacements and I did not replace the largest cap but that > didn't help. I've also taken out all transistors and diodes and checked > them out of circuit. > > The next thing I was going to do was test the potentiometers. I've used > contact cleaner in them and they seem clean but they should be tested. > > Santo > > On Wed, Jul 12, 2023 at 11:16 AM Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de> > wrote: > >> On 7/12/23 16:36, Santo Nucifora wrote: >> > I am trying to fix a Commodore PET Educator 64 model that has video >> > issues. There is no schematic that I could find for the board marked >> > with a part number of "02-96409 REV 3". Would anyone have a schematic >> > for it? >> > >> > Here is a picture, if it helps: >> > >> https://vintagecomputer.ca/wp-content/uploads/2023/07/Educator64-02-96409Rev3-videoboard-scaled.jpg >> < >> https://vintagecomputer.ca/wp-content/uploads/2023/07/Educator64-02-96409Rev3-videoboard-scaled.jpg >> > >> > >> > From my understanding, the monitor in the Educator 64 allows for >> shades >> > of grey (or green in this case) and is not a standard PET monitor so it >> > may be specific to the Educator 64 only. This monitor will run with >> > signals from an unmodified C64 motherboard. The PET 64, however, has >> > extra circuitry on a small daughterboard that changes the video signal >> > to black and white so that a normal PET monitor will work. >> > >> > I currently have vertical collapse on this particular monitor. The >> video >> > output of the C64 via an external monitor is good so the signal should >> > be good as well. Having a schematic would help with diagnosing the >> > vertical circuit. >> >> Can't help you with the schematic, but the TDA1170 is the IC that >> controls the vertical deflection and a datasheet is easily available. >> The TDA1180 is for the horizontal part. >> >> You might also want to check the socketed NE556 on the left side. >> Sockets can develop contact problems over time and this doesn't look >> like a quality socket. Same goes for all the potentiometers and that >> little switch. >> >> Gerrit >> >> >> >>Received on 2023-07-12 20:00:08
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