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View Full Version : CBM PC10-III on-board video card problem - Plantronics ColorPlus compatible



archeocomp
August 6th, 2017, 09:54 AM
Hi Folks, I dug out my Commodore PC10-II and PC10-III CGA equipped machines after long long time. They both worked for a while when the smaller brother PC10-III suddenly died. Now it only beeps one long two short which indicates (IMHO) video card problem. What's even worse, I can not get VGA work in it now - before when on-board CGA was functional I could also use VGA. So it looks like I have nice doorstep :-(

It uses excellent Paradise PVC4 chip
http://www.vcfed.org/forum/showthread.php?46748-Paradise-PVC4-Composite-Artifact-Mode-Fun

First question - what that error actually says, is the PVC4 chip dead or is there any hope that it is the CGA RAM only?
Second question -would any diagnostic EPROM help in this particular computer? VGA, and/or on board CGA are not working ..

If there is hope that it is only CGA RAM I am willing to try to unsolder them. I surely have two DRAM 4x64kB spares.

Flamin Joe
August 6th, 2017, 06:48 PM
Second question -would any diagnostic EPROM help in this particular computer? VGA, and/or on board CGA are not working ..

A diagnostic EPROM like Supersoft/Landmark (http://minuszerodegrees.net/supersoft_landmark/Supersoft%20Landmark%20ROM.htm) will still work in this case. If it can't initialise the video the diagnosis will be done by beeps from the PC speaker of which you will need to refer to the manual to understand what it means. Just run it without the VGA card as VGA is not supported by anyway.

archeocomp
August 13th, 2017, 07:35 AM
As described on the pages it sometimes behaves weirdl. I got following errors (with working keyboard attached):
1 Hi/Lo - 4 short beeps - 8254 Timer 0
2 Hi/Lo - 9 short beeps - NMI
3 Hi/Lo - 2 short beeps - Keyboard scan lines
BTW it is second time in a month or so, that I populated EPROM into socket reversed and in both cases the EPROM survived although I could see in both cases LIGHT in the chip's window.