CDROM2 glitches when warm.

atman · 05/07/2016, 03:01 AM

Searched but could not find any similar problems.

I got the briefcase setup working yesterday thanks to Fidde_se.

The CD could very well read PCE games and played well. BUT, when I play for like 10min it will get unstable. It seems like it can read the games but the grapic will glitch out. Sometimes it will get stuck in a reading loop or someting and freezes.

When i reboot it will start up and so on, but works much worse than if its cold rebooted.

Whats is the problem, is it a weak laser?
Tried clean the connector with alcohol but no improvements.

Fidde_se · 05/07/2016, 01:50 PM

New caps and maybe a pot tweak on laser...

How's the gear?

atman · 05/07/2016, 01:58 PM

The gear is new and alright.
Caps and calibration I have no clue. My guess is that caps is original.

Do you do recapping?

Fidde_se · 05/07/2016, 02:25 PM

Yes, but can't swear on that it will fix it =)

Keith Courage · 05/07/2016, 02:39 PM

Most likely the CD drive just needs some potentiometer adjustment. This is usually the case if the CD drive works fine on a cold start but starts getting glitchy after it warms up.

atman · 05/07/2016, 02:45 PM

Thanks for the response.

Think I saw a tutorial here on pot adjustments. I will start with that.

Keith Courage · 05/07/2016, 07:01 PM

generally any of these 3 pots(circled in red) could be the culprit. So try them first. Just try one at a time. Rarely ever do the other two need to be changed.

atman · 05/08/2016, 12:33 AM

Does the white pc engine looks the same?

Keith Courage · 05/08/2016, 12:55 AM

Usually, sometimes the pots can be all black. Either way same configuration.

atman · 05/08/2016, 02:30 AM

Does it matter if its a CD-R disc?

I mean, it seems like it can read the disc but it glitches. Thought if was any problems reading it would be noticed in the seeking..

Keith Courage · 05/08/2016, 02:50 AM

Not every Drive is created equal when it comes to reading a CDR discs. So no matter what you do, you could have some issues with them. Not to mention, a good majority of the Rips found online are not good. Meaning they are glitchy and can cause issues. Also, a big factor can be what type of media you are using. I typically find that using something with a lighter green bottom on the disc works better with these systems then higher-quality discs with darker green bottoms do.

atman · 05/08/2016, 02:54 AM

OK, will get a original silver-disc and see if there is a difference. Might be best to start there and rule out things.

Heard that it might be better if using an old CD-Writer? They have more power or something?

Keith Courage · 05/08/2016, 01:53 PM

I've honestly heard this about using an old CD writer but I've never noticed a difference. As long as your CD burner can burn at ten times or slower that should be good enough.

wildfruit · 05/08/2016, 03:52 PM

I use this at the slowest it will go which is 8x, no problems
https://www.amazon.co.uk/LiteOn-IHAS124-14-SATA-Internal-DVDRW/dp/B00ERJXTE4

atman · 05/09/2016, 05:00 AM

I noticed when I adjusted the pots that the drive was quite warm. (Had the bottom on without screws to be able to test quickly)
Since I had trouble with my IFU I feed it with 10v directly, original is like.. 8V? The 7805 might be warmer than necessary and cause the drive to get more sensitive.

Just a thought..

Anyways, I have adjusted the far right pot. Well, it clicked a bit the first time i touched it. But its best in the position it was from the beginning. Also its much better, not 100%, but an improvement.

Will continue with pot tweaking..

Fidde_se · 05/09/2016, 06:00 AM

7805 with proper heatsink can be feeded with 35-40v without problems according to specs so an few extra volt shouldn't make it that much warmer, then there's the new switching regulators that can replace them completely that doesn't get warm at all.

Like Recom R-78HB5.0

atman · 05/09/2016, 08:41 AM

Im change some regulators to this one. Like in the IFU, some AV Famicoms etc.

https://www.elfa.se/sv/spaenningsregulator-to-220-st-l7805cv/p/17326242?q=73-262-42&page=1&origPos=1&origPageSize=50&simi=98.11

Dunno if its the most optimal, but its not near as warm as the original ones.

Edit: linked the wrong one.

atman · 05/10/2016, 05:10 AM

Quote from: wildfruit on 05/08/2016, 03:52 PMI use this at the slowest it will go which is 8x, no problems
https://www.amazon.co.uk/LiteOn-IHAS124-14-SATA-Internal-DVDRW/dp/B00ERJXTE4

I found an old Plextor CD-R writer from 2002 that I tried with.
Noticed at once that it writes much slower, the lead-in and out takes like 3 min each. 1X writing on my modern CD-Burner took like 15 sec. So it really writes slow on all tracks.
Hope to get some improvements.

Fidde_se · 05/10/2016, 05:41 AM

The regulator from ELFA is still a pretty standard regulator and won't be much different from the one that once sat there, the modern are switched.

And the price for the modern once are like x20
https://www.elfa.se/search?q=r-78+5.0

The efficiency and difference in temperature can not be compared on the same day...

atman · 06/10/2016, 07:15 AM

Just for the record.

Fixed the glitching CDROM2 now. Worked OK when cold but a bit shaky when warm. Some games did not even want to start when it was warm.

Changed the 4.7uf caps, three of them had very bad values and one didnt even charge up at all.
After that the CDROM2 became stable.

Seems like the 4,7uf ones are the most likely to fail?

choijimmy · 06/10/2016, 08:49 AM

Yes, those 4.7uf caps failed quite often.