Kahenraz wrote on 2022-01-19, 00:42:

Maybe it's a silicone adhesive. I think its purpose is to dissipate vibrations from large components and redirect them away from the solder joints.

Could be, if they chose the wrong one, it releases acetic acid as it degrades, then the black color would probably be black copper oxide as it eats into traces.

I've examined all of my synthesizers and even my SC-88VL which has a similar layout but uses what appears to be a different kind of adhesive material on this capacitor. You may be correct that this was an error during manufacture of my SC-55mkII.

My much older CM-32L also uses some kind of adhesive under it's large capacitors but they have not caused any corrosion to either the PCB or any traces.

Kahenraz wrote on 2022-01-19, 00:42:

Maybe it's a silicone adhesive. I think its purpose is to dissipate vibrations from large components and redirect them away from the solder joints.

Though sometimes the silicone is used on coils to keep them from vibrating, in this case I think it's just to keep the larger capacitors in place during the wave soldering process.

I think all SC-55mkII use this brown adhesive (at least mine and a few others I've seen do), I never really wanted to mess with it as it works fine but your findings on the other thread are interesting.

I've completed my repair and written a thorough log of the process and my experience. Lots of photos and some further investigation at the very end after having examined all of my synthesizers.

PCB destroying adhesive found in my Roland Sound Canvas SC-55mkII (inspect your synthesizer!)

I also found cracks in solder joints (some quite large) around the rear I/O ports when inspecting the PCBs of my SC-55mkII and SC-88VL. This may be another thing worth looking at if you ever plan on doing maintenance on the mainboard of any synthesizer in the future.

Kahenraz wrote on 2022-01-19, 05:43:

I've completed my repair and written a thorough log of the process and my experience. Lots of photos and some further investigation at the very end after having examined all of my synthesizers.

PCB destroying adhesive found in my Roland Sound Canvas SC-55mkII (inspect your synthesizer!)

I also found cracks in solder joints (some quite large) around the rear I/O ports when inspecting the PCBs of my SC-55mkII and SC-88VL. This may be another thing worth looking at if you ever plan on doing maintenance on the mainboard of any synthesizer in the future.

I/O ports are where I would expect solder joint cracks and not just on Synths but pretty much any bit of equipment.. Laptops are especially bad for this issue.

I only meant that if you're ever planning to take apart your synthesizer, I wanted to affirm that 100% of the two I've inspected have serious cracks. Maybe this information will be useful to someone in the future.

Within the last 6-7 days, I modified my Sony PVM-9L1 to allow RGB signal from a video game console (my Genesis Model 1 with the multi A/V adapter that I built close to 3 years ago). Took a lot of trial and error to get it to work correctly (red signal wasn't working well, blanking didn't work or barely worked, and the tube didn't receive power) and after fixing those issues, it works without issues.

Going to order an Everdrive clone for my Genesis Model 1 so I can run the grid pattern test to make minor adjustments from H STAT to geometry to make everything perfect.

The board I designed is a mess and it'll be a cleaner job once I order more and better parts. Plus, it'll go inside of the PVM rather than the outside of the PVM.

Spent the last 2 hours trying to stop the flicker in a 17" CRT, even at 120hz there is a slight shimmer to the screen, either I have adapted to LCD panels to the point I cant use a CRT anymore or its an issue with the GPU or perhaps the CRT itself. (its not a big shimmer but rather one that is just perceptible to me if I focus on the screen, very strange issue for me) Might even be windows 98 doing it.

Quite frankly its giving me a nasty headache ...perhaps I need to stick to 800x600 and lower as the shimmer/flicker is not irritating at lower resolutions.

I have a 20" 4:3 Dell LCD I might switch to if I cant figure out the reason for the shimmering.

Shimmer could be the moire vibrating, it has to do with dot pattern in the graphics of the image you are looking at or the grid aperture is vibrating inside the CRT and is not repairable.

If you have another CRT monitor, give it a test to rule this out.

Cheers,

pentiumspeed wrote on 2022-01-20, 15:10:

Shimmer could be the moire vibrating, it has to do with dot pattern in the graphics of the image you are looking at or the grid aperture is vibrating inside the CRT and is not repairable.

If you have another CRT monitor, give it a test to rule this out.

Cheers,

Its a flat screen Trinitron type of CRT and its the only one I have right now so if I can figure out what up with it I would prefer that option.
Seems to function better under DOS modes, windows seems to produce highly irritating shimmer tho, its running off a S3 Stealth 3d 2000 so Im going to swap to a Voodoo 4 and see if that changes it.

Maybe caps on the output side need a refresh, I remember a few cards starting to get a wiggle on when they had aged.

BitWrangler wrote on 2022-01-20, 15:22:

Maybe caps on the output side need a refresh, I remember a few cards starting to get a wiggle on when they had aged.

Its an old PCI video card I got with a PC I bought .. Its possible it has issues, I didnt exactly test it when I got it 🤣.

I mean who tests S3 trio cards ?

TrashPanda wrote on 2022-01-20, 14:46:

Spent the last 2 hours trying to stop the flicker in a 17" CRT, even at 120hz there is a slight shimmer to the screen, either I have adapted to LCD panels to the point I cant use a CRT anymore or its an issue with the GPU or perhaps the CRT itself.

A side effect of either the high prescription on my glasses or the correction for astigmatism has made looking at CRTs painful to my eyes no matter what refresh rate is used; the lower it is the more it hurts. I looked at a 40 Hz CRT once and it was like someone was pressing ice picks into my skull through my eyeballs. Relief was instantaneous after increasing the refresh rate.

This wasn't placebo. I had never seen this monitor before and it was in a computer lab full of monitors. I could feel it piercing my eyes from across the room. The fact that it was also illuminated by a ceiling covered in cheap florescent lighting probably made it worse.

I happen to love CRTs but as a fact of life I can't tolerate them anymore. If I remove my glasses it doesn't hurt at all. Of course, I also can't see a damn thing.

Got the cache sorted out nicely. The Elitegroup motherboard... what a pain to work with... Hopefully I can get it built up into a system and off my desk and get some footage of my 386 SX this weekend. I plan on putting in the SixPak to see if it'll work in there, I have a ScanMan I want to connect to it, and a very nice Reveal (with OPL) with an SCSI connector that would speed up boot time as currently I have an AHA 1540 in there driving just the CDROM. Before I swap it out I have another SCSI CDROM that I want to finally test.

Plus I just want that 386 back on my desk and not on the floor 😉

Today I added to my Big Box collection with a rather nice looking copy of Rebel Assault 2.

So, naturally, I played Rebel Assault 1 instead.

Over the last couple days, I've started pulling some machines off the shelf I haven't used in a while to make sure they're working still.

After LGR's recent video about the box for the eMachines eOne, I pulled my unit off the shelf - still working properly, except the flat CMOS battery I wouldn't have a clue how to get to. Finally imaged my V1.1 restore CD for it and put it up on archive.org - noticed someone had uploaded a V1.2 so downloaded it to try in hopes it installed 98SE instead of FE. Unfortunately it's still FE. Honestly I can't see any difference but I didn't dig that deep yet.

Also pulled two laptops down, my Compaq N800c and my LG LM50 - one P4m, one Pentium-M, both Radeon graphics based (one 7500, one 9200), both with Soundmax Audio hardware. Both booted into Windows ME fine, thankfully.

I did try something on a whim though, and installed Duke3D and Doom 2 on both. Turns out that both can do Soundblaster digital sounds in DOS boxes in Windows, and the LM50 could also manage MIDI in a DOS box (although with the Windows Roland softsynth). No Adlib/FM though, it seems. Still, better than I expected for machines meant to run XP, but forced to run ME.

I went through my collection of motherboards, decided which ones to sell and which to keep, and tested most of those that have to go. The collection is just getting too big for my taste, so I'll be selling at least 10 boards.

LHN91 wrote on 2022-01-22, 05:12:

Also pulled two laptops down, my Compaq N800c ...
.... Still, better than I expected for machines meant to run XP, but forced to run ME.

I think the N800c was just old enough and business class enough that Compaq offered Win98 as an option on it. Corporates clung on to 98 for several years until they got all their software ported to XP.

Cleaned the room, broke out the NEC Ready 9522 to prep it for E-bay, now I'm not so sure I'm getting rid of it. I got a wild hair and decided to fix the CMOS battery (sustainable CR2302 mod to the DS18827 compatible clock) as it had died, and and throw in a random PCI Graphics card I Got with the PC-Chips "PC-100" motherboard.....well....turns out it's a 3DFX Banshee, and the NEC did a superb job of just automatically detecting it and disabling the on-board video. Sheesh....putting Windows 98 Second Edition on it now, after throwing in a 250GB HDD (split into 4 partitions of course). Granted I only have a 4x cd-rom in it (from the currently in need of mending VersaDock), but it seems happy enough and found the CD-ROM drive so soo time to throw 98SE on it and make it a happy camper again with copious amounts of drive space.

Solid bit of NECromancing there.