iridude Posted March 17, 2021 Share Posted March 17, 2021 I just got this console and guessing ram issue. This is what it displays without cartridge Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted March 17, 2021 Share Posted March 17, 2021 3 minutes ago, iridude said: I just got this console and guessing ram issue. This is what it displays without cartridge Yes, likely the VRAM causing the problem. However, this is often simply caused by a poor power supply or a dirty power switch - both common problems with the CV at this age. Are you able to measure voltages? Quote Link to comment Share on other sites More sharing options...
iridude Posted March 17, 2021 Author Share Posted March 17, 2021 (edited) Yes, the power supply that came with this for sure bad +5v rail showing only 2V. The one doesn't even power up using that power supply. How to open power supply's? Worth to refurbish them? However, I used a known good power supply and shows this. I haven't opened up yet. Edited March 17, 2021 by iridude Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted March 17, 2021 Share Posted March 17, 2021 6 minutes ago, iridude said: Yes, the power supply that came with this for sure bad +5v rail showing only 2V. The one doesn't even power up using that power supply. How to open power supply's? Worth to refurbish them? However, I used a known good power supply and shows this. I haven't opened up yet. The CV power supplies are sealed and have to be cut open if you want to refurbish them. Also, a large portion of the insides is filled with epoxy. It is possible to do some refurb on them but a lot of work and not worth it in my opinion. Even a seemingly good power supply can have voltages dip below acceptable levels when under load so best to open up the CV and measure the voltages with the CV powered on. Quote Link to comment Share on other sites More sharing options...
crisalan44 Posted March 17, 2021 Share Posted March 17, 2021 (edited) That is a bad ram chip on U10, I did the tests and screen shots on this issue for Kamshaft and his excellent website Colecovision Addicts. If you go to the site and look up fixing ram via screen shots you will see the exact same picture you posted under the U10 ram slot(I believe it is the first picture). They sell kits at console5 also to do it yourself. Here is the link to CA. Cheers and good luck! Sorry I should have read the post above more thoroughly before I posted, I see you are already aware of this issue. https://cvaddict.com/article.php?articleid=19 Edited March 17, 2021 by crisalan44 1 Quote Link to comment Share on other sites More sharing options...
Ikrananka Posted March 17, 2021 Share Posted March 17, 2021 1 hour ago, crisalan44 said: That is a bad ram chip on U10, I did the tests and screen shots on this issue for Kamshaft and his excellent website Colecovision Addicts. If you go to the site and look up fixing ram via screen shots you will see the exact same picture you posted under the U10 ram slot(I believe it is the first picture). They sell kits at console5 also to do it yourself. Here is the link to CA. Cheers and good luck! Sorry I should have read the post above more thoroughly before I posted, I see you are already aware of this issue. https://cvaddict.com/article.php?articleid=19 Wow - I must have been asleep under a rock - wasn't aware of Kamshaft's article on this and those are great screenshots. I do still believe that the voltages should be checked beforehand. Each VRAM chip will have slightly different voltage tolerances and as such perhaps U10 in this CV is slightly less tolerant than others. 1 Quote Link to comment Share on other sites More sharing options...
crisalan44 Posted March 18, 2021 Share Posted March 18, 2021 1 hour ago, Ikrananka said: Wow - I must have been asleep under a rock - wasn't aware of Kamshaft's article on this and those are great screenshots. I do still believe that the voltages should be checked beforehand. Each VRAM chip will have slightly different voltage tolerances and as such perhaps U10 in this CV is slightly less tolerant than others. 100% agree with your approach!! Quote Link to comment Share on other sites More sharing options...
iridude Posted March 19, 2021 Author Share Posted March 19, 2021 I opened up power supply and behold for sure at least one blown capacitor. I seen that console5 has a kit but out. Anywhere else you can get replacement caps, etc for the power supply? Quote Link to comment Share on other sites More sharing options...
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