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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: dkire13 on December 01, 2024, 02:02:24 AM
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Bit of a long post, sorry, but wanna be as thorough as possible.
Recently acquired my first system, it's a standard (white) PC Engine and CD-ROM2 with the IFU-30 (and a Super CD 3.00 card). CD unit was dead out of the box (go figure) and needed the infamous gear. There were also issues with the laser, which would not focus. This was all cleared with a recap.
After that, it was working great. Read the two CD games I had with no issue as well as two audio CDs that I tried as well. The recap was making it clear that the console needed one too, since the PSG was much quieter than CD audio, barely audible. It sat dormant for a few days before I got around to it, but I recapped the console, which now also works with no issues.
Unfortunately, either as a result of that recap, sitting dormant, or just my luck, the console stopped booting CDs entirely. The drive itself would not consistently go into "PC" mode when pushing run on the bios screen. After lots of tinkering, troubleshooting, and checking my work once and twice over, and recapping the IFU, I discovered that the only way to affect change was by whether the socketed backup RAM board was connected or not.
With the BRAM board connected:
- System rarely, if ever, manages to kick the cd-rom2 into PC mode. It functions as if the console wasn't on, playing discs through the bus connector out of the speakers just fine. Bios hangs on "please wait".
- Audio CDs will not load from the bios. Playing a disc while the console is off or playing a HuCard works fine.
- Both games I have on hand also hang upon loading. Stuck on the "please wait" screen. About 50% of the time, Macross: Eternal Love Song will make the drive go berserk, blanking the little LCD and causing the disc to spin incredibly fast. You have to switch power off of the IFU to get it to stop.
- Pushing select on the bios screen to access the save RAM loads three options with heavily corrupted text. Only the Japanese parts are affected, the english parts at the top are fine. Formatting says "ok" but has no effect. Staying for too long on the delete screen (about 5 seconds) makes the first couple lines go wavy before the system hard crashes. Leaving a white or black screen with two grey rectangles overlapping the top edge. Something to note is that the corrupted text is not random. It shows the same pattern every time.
With the BRAM board disconnected:
- cd-rom2 is now significantly more stable and responsive. Goes into PC mode 100% of the time.
- Audio CDs now boot and play with no issues on the CD card interface. Tested both outer and inner tracks, fast forwards and rewinds. Reads fine.
- Puyo Puyo CD now boots to the title screen and menu. CD audio will play and all appears normal. Attempting to select any game mode makes the drive seek and the game proceeds to hang. Selecting tutorial will occasionally bring you to a solid white screen where PSG music will play and the game appears to be functioning correctly, but you can't see it. Losing seems to soft lock it. I once got single player to load a very corrupted red background with the cloud background tiles and nothing else. Hard crash. This game has a splash screen to warn you if there is not enough space for it in the save RAM, and this screen was appearing before the console recap, indicating that this problem existed in some capacity already.
- Macross: Eternal Love Song crashes on loadup, and will usually reboot you straight to the bios. In no circumstance does the drive blank and go spin dizzy like it did before.
- Pushing select on the bios screen to access the save RAM loads the same three options, though this time with solid white rectangles instead of any corrupted characters. English still unaffected. Formatting says "ok" but still has no effect (duh). Deletion menu no longer has the same crash as before.
The Super Cap (which I didn't replace) does still hold a charge of about 5 volts when the board is disconnected. HuCards work in any configuration, which makes sense. CD-ROM runs as expected when its just sitting in the IFU. I don't appear to be the first person to be having this issue cause I found evidence of something similar here:
https://www.reddit.com/r/consolerepair/comments/1cafgqx/pc_engine_interface_unit_corrupted_bram (https://www.reddit.com/r/consolerepair/comments/1cafgqx/pc_engine_interface_unit_corrupted_bram)
(His text is much less corrupted than mine, but similar symptoms.)
Kinda at wit's end here, thanks for reading this all. ](*,) What's the next step I should try? Are there any CD games that never check for the BRAM that I could burn and test?
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The problem symptoms you describe sounds like what happens when one of the Bram chips go bad. The solution is to replace the bad chip, replace the Bram module(can only be found out of other IFU docks), or replace the dock altogether.
I doubt it was something that happened from doing a capacitor change on the PCE itself. Although you could always mail the PCE to someone to test with their dock to find out for sure.
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Well, that sucks. Good to know I probably didn't kill it, at least. I'll try to do an FRAM swap (eventually) and report back if that solves it.
I can't get over the timing, though. It worked for a day before coincidentally developing another issue. Just my luck, haha.
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The Fram mod won't fix it. The save ram chip that holds game saves and the Ram chips(two of them)that game data is loaded into are completely different.
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Oh, I misunderstood. Are there any modern replacements for those like there is for the save RAM, or are you stuck tracking down old stock of the M5M5256BFP-70?
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I don't think there are any new replacements that I know of. Lucky for you, there appear to be some cheap old stock chips on ebay right now. https://www.ebay.com/itm/196552080638?_skw=M5M5256BFP-70&epid=4070441832&itmmeta=01JEX7DD4KKZ2FEG8SJRQGQ0HY&hash=item2dc36abcfe:g:l~UAAOSwLKlmtp2s&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKnzHPOFvQ5sUV8UDYbTCN9zzGCz73Y%2FQZZfsIIbA9aCmCaT8Xm%2FEFcjXcNFOO7ulb8UF%2FoIbriZb0%2FxNaUystDd%2B5snBGItnz1H7vBjosh3QRVSlXK3kjzVz0MA0wC0fgMt1Y7fd5O0NQT2Noe8V1hcb799rQAuZJsxshgLI8p5iP%2F8IcQop9pl3iM9ic%2FOD%2FhaEhRI%2BYXwHrRa730Aik3pXcmtinDYXHtfpBP3pWLEOIsi8BRIGSZUpQ0lJBQrePE%3D%7Ctkp%3ABk9SR7TStaf3ZA
I'd probabaly just buy one as it's normally only one chip that's bad but I suppose you could get two just in case.