Thermalwrong wrote on 2023-11-29, 03:08:

Heh I give up for now, this took so dang long. I lost so many of the smaller capacitors & resistors somehow and it took ages to find them, bend the legs, trim the legs. Check the values etc.

Here's how it fits in the slot of one of my mini SBC computers. I wanted to just use it in the big testing PC since that's got the remnants of a real case to check fitment, but for this initial testing I needed -5v and to be able to see power consumption

Good news and bad news...... the ISA connector works though and it's not falling off. The glue is more of a space filler, those metal legs inside the fibreglass are giving all the important mechanical strength it needs, more now with the traces soldered on too.

Bravo. Well done!

DerBaum wrote on 2023-11-28, 03:50:

I see no reason why it shouldnt work. That looks great. :thumbsup: […]
Show full quote

Thermalwrong wrote on 2023-11-28, 03:36:

Here's how the front and back look close up, ignore the possibly shorting loose traces wires, those will get secured once I know things work.
finished trace rebuild.jpg

I see no reason why it shouldnt work.
That looks great. 👍

edit: Ok maybe i see a reason near JYEN jumper... traces seem broken there

Well spotted 😀 I fixed that but I should've checked the hi-res PCB scans before attempting the rebuild, there was more broken including Address 7 on the ISA bus was severed further up by the 22X/24X jumpers. The initial test was rather disappointing.

appiah4 wrote on 2023-11-29, 11:01:

Thermalwrong wrote on 2023-11-29, 03:08:

Good news and bad news...... the ISA connector works though and it's not falling off. The glue is more of a space filler, those metal legs inside the fibreglass are giving all the important mechanical strength it needs, more now with the traces soldered on too.

And the bad news is?..

It's still broken of course! 😁
So there's good news and bad news because at this point I've verified that the card's FM part works, which is fantastic - that means the address and data pins on the ISA connector are working and the audio section is functioning. The YM3812 & Y3014 FM DAC are both functional. If that works, that means the CT1336 chip is doing its thing too, that's the important one since it can't easily be replaced.

The bad news of course is that the sound blaster isn't blasting, specifically the CT1351V201 chip isn't responding to any commands with the Snark Barker's SBDIAG test program, which absolutely should work even though it's designed for a Soundblaster 1.0/1.5 PCB. The crystal is resonating at 12MHz as it should and I'm pretty sure the power & data lines going to the DSP are all still good, so it should be working.
To test it some some more I pulled the chip back off and tested it with the TL866 where it seems to read okay as an AT89S51 but when I put the DSP onto my SB 2.0 clone card which conveniently has a socket, it fails in the same way as it does on the original card.
I'm pretty sure that the DSP on my clone card and the SB2.0 are interchangeable because it's a standard microcontroller and the Snark Barker reproduction's firmware on the github is the same as this card uses.

Next thing I'm gonna put a socket on the card and order some replacement PLCC44 AT89S51 chips 😀

CrazyCatman wrote on 2023-11-29, 06:44:

Spent time dismantling an IBM ThinkPad 760 XL which no longer starts up (before dismantling), but just have a speaker symbol flashing. I read that it could be just the switch for hibernation, but that didn't seem to be the case. I also read that it could be most likely the main system board or the power board.
I tested the PSU and it gives 16.4 V which is close to the 16 V DC it says.

Check under the palm rest, you can unscrew that just by lifting up the keyboard tray. There's 4 screws underneath from what I recall and then the plastic can be rotated upwards to remove it.
There's a standby battery inside that area which is unfortunately a NiMH cell, which sadly afflicts all Thinkpad 760 series - my 760LD needed some trace repair in there after cleaning up all the battery corrosion.
The PCB in there is fairly simple though with maybe only 2 layers, it hooks up some RTC stuff and the keyboard from what I recall.

Ideally it would've been best to check that battery first before pulling the rest of the laptop apart. The board sandwich inside is less likely to have faults.
Additionally - the Thinkpads support POST code reading through the parallel port so you can get a standard parallel POST code reader to check what stage of the boot process it's getting to.

That is an SB 2.0 If I'm not wrong.. You have -5V on the testing rig right?

Been fixing phat PS3s. Here's the tally so far:

- CECHM03, 80GB - supposedly a interesting variant where it came with two different mainboard revisions - there are reports of people finding VER-001 boards (which is the same as CECHL/P/Q units) and some reported DIA-001 (CECHH). Was previously delidded (and apart from abysmal thermal paste used, the delid was pretty cleanly done!) so I just replaced the old paste with MX6 all round. It's surprisingly more silent than CECHK04.

-CECHG04, 40GB - YLODs, has had only the RSX delidded. I suspect the caps being toast on the backside (the one that is accessible when you remove the top shielding) as it does look quite old and withered.

-CECHC04, 60GB - same as the G04, except it's also CELL delidded like the M03 - this one is 100% the caps as they have burn marks on the film inside.

appiah4 wrote on 2023-11-29, 16:27:

That is an SB 2.0 If I'm not wrong.. You have -5V on the testing rig right?

I'm wondering the same thing. Does that pico PSU give you -5V? You might want to try a Voltage Blaster.

appiah4 wrote on 2023-11-29, 16:27:

That is an SB 2.0 If I'm not wrong.. You have -5V on the testing rig right?

Yeah it's got -5v, the riser is my own design and it's got an add-on board to add -5v. Nowadays I'd probably just add a 7905 but this little module works properly 😀
The card you see the blue PLCC44 to DIP40 adapter plugged into is actually a veeeery similar clone, the Media Concept 2.0 apparently: Anchor Electronics - Media Concept 2.0 Souncard - SB 2.0 clone with real OPL2
I could similarly test this chip on the Snark Barker production board since that's got a socket, but this adapter has those big square pins which will ruin sockets pretty quickly.

The test program I'm using is the SBDIAG utility that TubeTime made, it's doing some basic tests for the DSP like reset and get DSP version: https://github.com/schlae/snark-barker/tree/master/sbdiag
The original chip sadly fails any DSP tests on both the CT1350 and the clone card that's so similar it should absolutely work.

BTW, is anyone interested in reproduction Soundblaster 2.0 PCBs? I still need to finish the silkscreen for the remake PCB I made last year. Since it no longer needs to replace this original PCB I'll try to improve the silkscreen a bit with resistor & capacitor values. The rebuild had a positive outcome as well, I fixed a mistake in my schematic, a resistor value was wrong 😀
Taking a repair to the extreme - Remaking Soundblaster 2.0 CT1350B PCB

I'd be interested in a PCB if shipping isn't excessively prohibitive..

I always wanted an external Zip 100 SCSI drive but prices for a working unit are prohibitive.

Yesterday while I was in the storage room of a customer I saw it, that case with that color is instantly recognizable.
I grabbed it and "oh no!" it had cracks all over the back of the case, but the worst thing is that it was making rattling sounds from inside.

Still decided to pick it up, the customer didn't even remember having it.

At home I opened it and thank goodness the mechanism was just dislocated, nothing was broken! Reassembled everything, glued the sad case, fetched a compatible PSU and... yay!
The unit powered up and was accepting (and ejecting) the disk happily!

Only one thing was missing the SCSI cable so I ordered the cheapest solution I found on amazon, a RS-232 cable with DB25 connectors. The item description declared that all the 25 lines have a pin to pin connection, so I had high hopes that it would work.

And indeed it works! Finally I can exchange files with my Power Mac 7100/80 without burning CD-Rs! Very happy about it, and now since the case is already mengled I was thinking to convert it to use an USB power source.

I did some benchmark for fun:

Contender #1
* Cyrix 5x86 (Socket 3) 120Mhz, cache have read 1WS, Write 0WS, Writethru, FSB40
* 64MB FPM (Read 0WS, Write 1WS)
* 8GB CF Storage

Contender #2
* Ryzen 3950X
* 32GB DDR4 3200 (14-16-16-16-38)
* 1TB NVME GEN4 storage

Test 1 : Post time : Winner : The 486
Test 2 : From power button to Desktop, so it include POST (486 have Nt4, Ryzen have Arch Linux) : Winner : The 486
Test 3 : From desktop, launching a period correct word processor (486 have Word 97, Ryzen have Libre Office) : Winner : The 486

Conclusion : They should outlaw bloat.

kingcake wrote on 2023-11-26, 20:20:

Thermalwrong wrote on 2023-11-26, 14:38:

Wow, that board looks like it should be fun to use, with PCI and EISA. Good job catching the bad capacitors before they could do […]
Show full quote

Wow, that board looks like it should be fun to use, with PCI and EISA. Good job catching the bad capacitors before they could do more damage 😀
Also that big regulator looks like it's missing the heatsink. Is that just while fixing it or it's really missing? It looks very similar to the heatsink on my AN430TX Intel board

appiah4 wrote on 2023-11-26, 09:36:

Does it actually work? I have one of these and tried to erase EEPROMs with it, and it did nothing..

Maybe it needs a couple of runs through? If it's a UVC lamp tube it should work.
Looking around I can see that UV sterilizer boxes for phones / small stuff are a thing and they have UVC lamp tubes in too - but no one's buying them so they're super cheap now, £4. I'm getting a UVC lamp type box and a UVC LED that's rechargeable to see how well they perform 😀 I've got a few UV eraseable EPROMs that I've never been able to do anything with.

Don't waste your time with LED based devices. Real UV LEDs are mega expensive. The LEDs in those cheap devices are more purple than UV.

This topic set me off on a tangent to learn about UVC and what EPROMs require to erase. I've tried erasing EPROMs with a window using visible UV torches exposing for ages but that didn't do a thing.

Following these posts I bought a £4 UVC tube based phone steriliser and a £6 Homedics UV Phone Sanitizer which uses LEDs, worth checking out for just a tenner 😀 I have enough UV-erasable EPROMs that I can't use that it's worth doing.
I tested out both at erasing EPROMs and I was surprised at how effective the LED type actually is - the real UVC LEDs can be identified by the gold colour housing. I'll bet this wasn't cheap to manufacture but now no-one's buying consumer sterilisation equipment, this can be had for ridiculously cheap where I'm pretty sure it's being sold below cost price now:

Here's the tube type sanitiser, I modified it so both tubes are on the same side and disabled the speaker which had ridiculous voice prompts, apparently this thing does aromatherapy for phones 🤣. It's built so ridiculously cheaply it doesn't have a lid-open sensor so I can do all the eye & skin damage I want with it.

But it came with a UVC test strip and here's the comparison between the two. Not a fair comparison though, the LED sanitiser's power output has been doubled while I don't know how / want to modify the tube sanitiser apart from moving the tubes. The tube sanitiser is probably not indicative of output power with all UVC tube lights, I suspect it's running the tubes at quite low power, they only draw 500ma at 5v. Better tube lamps probably give more output.

To improve the power output on the LED phone sanitiser I followed the instructions here, to boost the power output to around 2x standard. It runs for 30 seconds each time which seems short but it's rather effective - here's what it does now:

Because the LED light is concentrated in one spot it's really perfect for the EPROM window, which is blasted thoroughly enough that the EPROM is successfully blanked in 4 minutes with 8x button presses. For comparison, the UVC tube sanitiser clears the EPROM in 30 minutes quite reliably.
Now all my EPROMs are blank and ready for use 😀

Time to dust off this baby - Abit SH6 motherboard

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me.

The quality is absolutely crisp. I don't think I've seen VHS tapes play this clean besides Panasonics.

Excuse the noobish question, but I never had a PC with more than 2 serial ports back in the day...

I want 4 serial ports on my 386 rig. And I'm looking at com port config charts like this.

Com 1 and 2 are on a 16-bit ISA Winbond I/O card. I'm adding in a 2 port 8-bit ISA serial card (non PnP, uses jumpers)

So does this mean if I have a mouse using the interrupt all the time on COM1 I won't be able to use a modem on COM3 simultaneously due to the IRQ 'sharing'?

vmr_ wrote on 2023-11-30, 21:41:

Time to dust off this baby - Abit SH6 motherboard

And what appears to be a distinctly Canopus graphics card (which one, I can't tell).

kingcake wrote on 2023-12-01, 00:18:

Excuse the noobish question, but I never had a PC with more than 2 serial ports back in the day... […]
Show full quote

Excuse the noobish question, but I never had a PC with more than 2 serial ports back in the day...

I want 4 serial ports on my 386 rig. And I'm looking at com port config charts like this.

com ports.jpg

Com 1 and 2 are on a 16-bit ISA Winbond I/O card. I'm adding in a 2 port 8-bit ISA serial card (non PnP, uses jumpers)

So does this mean if I have a mouse using the interrupt all the time on COM1 I won't be able to use a modem on COM3 simultaneously due to the IRQ 'sharing'?

serial mice run about 1200 baud rate and should not interfere to much with a serial 33.6 or 56k modem on same IRQ. curious wht are you going to do with the other 2 serial ports...

Horun wrote on 2023-12-01, 03:08:

kingcake wrote on 2023-12-01, 00:18:

Excuse the noobish question, but I never had a PC with more than 2 serial ports back in the day... […]
Show full quote

Excuse the noobish question, but I never had a PC with more than 2 serial ports back in the day...

I want 4 serial ports on my 386 rig. And I'm looking at com port config charts like this.

com ports.jpg

Com 1 and 2 are on a 16-bit ISA Winbond I/O card. I'm adding in a 2 port 8-bit ISA serial card (non PnP, uses jumpers)

So does this mean if I have a mouse using the interrupt all the time on COM1 I won't be able to use a modem on COM3 simultaneously due to the IRQ 'sharing'?

serial mice run about 1200 baud rate and should not interfere to much with a serial 33.6 or 56k modem on same IRQ. curious wht are you going to do with the other 2 serial ports...

Com1: Mouse
Com2: External Modem
Com3 and 4: Test equipment like a Logic IC tester that talks via serial terminal

PcBytes wrote on 2023-11-30, 22:09:

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me. […]
Show full quote

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me.

The quality is absolutely crisp. I don't think I've seen VHS tapes play this clean besides Panasonics.

I bought this Panasonic PV-8451 for $6 to convert some old VHS tapes to digital. Thoughts on quality? They wanted $25 for Sonys that were rusty.

ODwilly wrote on 2023-12-01, 05:16:

PcBytes wrote on 2023-11-30, 22:09:

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me. […]
Show full quote

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me.

The quality is absolutely crisp. I don't think I've seen VHS tapes play this clean besides Panasonics.

I bought this Panasonic PV-8451 for $6 to convert some old VHS tapes to digital. Thoughts on quality? They wanted $25 for Sonys that were rusty.

Does it have time base correction? You really want TBC for digitizing VHS. It's quite common to use a VHS camcorder to output to a digitizer since they almost all have TBC.

ODwilly wrote on 2023-12-01, 05:16:

PcBytes wrote on 2023-11-30, 22:09:

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me. […]
Show full quote

Been testing my ole' trusty Grundig GV729M VCR after I had a friend clean its heads for me.

The quality is absolutely crisp. I don't think I've seen VHS tapes play this clean besides Panasonics.

I bought this Panasonic PV-8451 for $6 to convert some old VHS tapes to digital. Thoughts on quality? They wanted $25 for Sonys that were rusty.

Ran one of those years back, output was crisp to TV, dunno about to capture card. May have to use a Rage Theatre card for it's special magicks.