Resin Injection CRT Cataract Surgery On Macintosh Monitor

Nothing lasts forever, but you’d think the leaded-glass face of a CRT would not be a place you’re likely to see Father Time causing failures. Alas, the particle accelerators we all lovingly stared at were very often not unitary pieces of glass: in case of implosion, safety glass was glued onto the front of the CRT. That glue will inevitably fail, as happened to the 20″ Mac-branded Triniton [Epictronics] had with a PowerPC 6100 that needed a few other repairs.

His version of cataract surgery was the most interesting. Usually cataracts are an issue for much older CRTs than the 90s-era Macintosh display featured here, but this particular display was literally pulled out of the trash and not stored well before that, so that’s probably what accounts for its accelerated aging. Usually what people do with CRT Cataracts is use heat to remove the safety glass and failing adhesive. [Epictronics] has a safer technique, however: inject fresh adhesive into the gap that’s forming around the edge of the display.

With a syringe and UV cure resin, he slowly and laboriously goes around the edge of the display to fill in the bubbles that can be reached. Luckily, the delamination on this CRT doesn’t extend very far beyond the edges, so a standard syringe tip could reach all the problem areas.

It looks good now, but if it doesn’t hold, [Epictronics] points out he can still remove the glass with the traditional hot-air technique. We hope it holds up; this is a nice technique to try if you have a CRT with the early stages of cataract delamination. For future reference, it took about one milliliter of resin to fill each square centimeter of affected area, which implies the cataract gap is quite small indeed.

Having repaired the monitor by about fifteen minutes into the video, [Epictronics] spends the remaining seventeen minutes getting the Mac running with its original CD-ROM drive (that needed recapped) and a DOS compatibility card.

We’ve featured [Epictronics] repairs here before, like when he tore down and rebuilt an IBM Model F keyboard. 

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User Repair Of A Not User-Repairable Victron CCGX Issue

Power banks come in many sizes, and those that target construction sites are probably among the largest. The massive four ton unit based around lead-acid batteries which the [Buy it Fix it] YouTube channel got handed is a good example. Inside it are Victron CCGX inverters among a lot of other Victron electronics, with the control panel for the system throwing up an error that was deemed to be not user-serviceable. Naturally, this makes for a good challenge.

The exact error as thrown up on the central control panel is error #42, indicating a storage corruption issue on the device. According to the manual this means an issue with the internal flash memory that stores settings, serial numbers and WiFi credentials, requiring it to be shipped back to the manufacturer.

To further diagnose the issue, this Color Control unit was taken out of the power bank and coaxed onto a repair bench. This device has a whole host of Ethernet, CAN and other buses on the back, along with a USB host feature, but using the latter to reflash the firmware made no difference. Fortunately it’s just an embedded Linux system running on the System-on-Module and gaining remote SSH access was a snap due to easy root access.

Interestingly, running a diagnostic on the flash IC showed it to be still in good condition. Instead an ECC issue was logged that caused it to be marked as bad. This seems to have been due to the flash IC requiring 4 bits of ECC per 528 bytes, but the software using only a single bit. After reformatting and clearing the error it seems to have fixed the issue. Apparently it was just a weird configuration error that soft-bricked the device, raising the question of how that happened.

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Diagnosing A Mysterious Fault With A Commodore 1541 Disk Drive

Some PCB corrosion on the bottom of the 1541 drive. (Credit: TheRetroChannel, YouTube)
Some PCB corrosion on the bottom of the 1541 drive. (Credit: TheRetroChannel, YouTube)

Recently [TheRetroChannel] came across an interesting failure mode on a Commodore 1541 5.25″ floppy disk drive, in the form of the activity LED blinking just once after power-up with the drive motor continuously spinning. Since the Flash Codes that Commodore implemented and bothered to document start at 2 flashes (for RAM-related Zero Page), this raised the question of what fault this drive had, and whether a single flash is some kind of undocumented error code.

A cursory check showed that the heads were okay and not shorted, ruling out a common fault with the used floppy mechanism. Cleaning up the corrosion on IC sockets and similar basic operations were performed next, without making a change, nor did removing the ICs to induce it to produce the documented error codes, but this helped narrow down the potential causes. Especially after swapping in known-good ICs failed to make a difference. One possibility was that the drive was boot looping, as the activity LED is lit up once on boot.

Some probing around with an oscilloscope between the faulty and a working drive seemed to point to a faulty RAM IC, but while probing the faulty drive suddenly initialized successfully. After some more poking around it appeared that the drive was fine after it had a chance to warm up, which just deepened the mystery.

The drive did talk to a C64 with diagnostic cartridge at this point, but would often glitch out. Ultimately it appears that a dodgy IC socket and a few bad traces were to blame for the behavior, making it an ‘obvious in hindsight’ repair. The bottom of the PCB had some clear corrosion on it, but the affected traces were apparently still hanging on for dear life with the drive still initializing once warmed up.

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Restoring A Commodore PET 3032 In Rough Condition

The restored PET/CBM 3032. (Credit: Drygol, retrohax.net)
The restored PET/CBM 3032. (Credit: Drygol, retrohax.net)

The Commodore CBM 3032 is a successor to the original Commodore PET 2001, yet due a conflicting trademark issue with Philips these first European PETs were called ‘CBM’ instead. Hence the labeling on the CBM 3032 that [Drygol] had in for a restoration, which would have been produced somewhere between 1979 and the cessation of its manufacturing a few years later. This former machine of the University of Szcezecin in Poland had languished in a basement until a local demoscene group came across it and wanted to use it, after a restoration.

Although at first glance from just the front it didn’t look too shabby, problems were apparent from just a walkaround, including rusty and buckled paneling, showing that the time spent in storage had not done it any favors. Internally there was decades worth of dust, along with a dodgy potentiometer, cold joints and some PCB-level bodges that may or may not have been there from the factory.

The main case was disassembled by drilling out the rivets to gain full access to every nook and cranny, allowing for a good cleaning and repainting prior to putting in fresh rivets. On the PCB side of things, a potentiometer and an LM340KC-12 linear regulator in a TO-3 package had to be replaced, after which the system managed to boot reliably once in every three attempts.

Fixing this took basically cleaning all contacts and IC sockets, as well as refurbishing the keyboard, with corrosion and the occasional broken trace causing a lot of grief. Ultimately the system was restored and ready to be put into demoscene service.

 

Fixing An Onkyo Receiver With Multiple Faults

Modern-day receivers are miracles of digital audio and video processing, but compared to their more analog brethren, they can come with a host of new and fascinating faults. The Onkyo TX-SA806 and SR806 receivers were released back in 2008, with [Tony359] recently getting the latter variant in for repair. Described as having weird digital distortion on the audio outputs, this particular issue got fixed by recapping the PCB with all the digital processing in the first video on this receiver, but this left the second issue unaddressed of a persistent hum, which is the topic of the second video on this repair.

Capacitor C5662 in the Onkyo TX-SR608 receiver with a slight bulge. (Credit: Tony359, YouTube)
Capacitor C5662 in the Onkyo TX-SR608 receiver with a slight bulge.

With the easy fix of recapping of the digital board already tried, next was a deep-dive into the receiver’s schematics to figure out where this low-frequency hum was coming from. With it sounding very much like mains frequency hum bleeding through, this was the starting point. Presumably somewhere on the power rails the normal filtering had broken down, so all rails had to be identified and checked for this interference.

With ripple on the 10V and 12V rails as well as the others seemingly in order, it wasn’t clear where the 100 Hz hum was coming from, but people on the BadCaps forum offered some help. After some back and forth it was deduced that the problem was the +15 VA rail, with heavy ripple on it due to a dead capacitor on the +22 V rail that comes straight from a transformer.

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How An Old Automatic Stoker Was Hacked Onto A Modern Lancashire Boiler

Usage of an automatic stoker. (Source: Claymills Pumping Station, YouTube)
Usage of an automatic stoker. (Source: Claymills Pumping Station, YouTube)

Hacks are of all ages, with the Victorian-era Claymills Pumping Station being no exception. When its old Lancashire boilers from the 19th century were  finally replaced with modern 1930s boilers, the 1920s-era automatic stokers were bodged onto the new boilers with a rather ill-fitting adapter plate, as there was no standard Lancashire boiler design. Nearly a hundred years later it was up to the volunteers at this Victorian-era pumping station to inspect and refurbish this solution, before fitting it back onto the boiler.

Lancashire boilers have two flue channels in which the coal is burned, which used to be done purely by hand. The automatic stokers are belt-driven devices that continuously add fresh fuel and massively lighten the workload. The 1920s stokers are still in place at this pumping station and a feature that they would love to retain.

Thus, after previously pressure-testing this #1 boiler to well beyond its operating pressure, the refurbished adapter plate was mounted back on with some percussive persuasion of the ‘very large beam’ variety.

Before the stokers could be mounted again, however, the boiler inspector had to give his OK to put the brickwork around the boiler back in place which helps to insulate it, among other functions. Once this is completed the boiler can finally see a fire again since it was last used in the 1970s. Whether these vintage stokers will work flawlessly will remain a surprise until then, but it’ll be a treat to see them operate.

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Fixing The Damage Of A Botched SNES SuperCIC Mod

Not what you want to see when testing that 'repaired' SNES. (Credit: Skawo, YouTube)
Not what you want to see when testing that ‘repaired’ SNES. (Credit: Skawo, YouTube)

The good part about older game consoles like the Super Nintendo is that they have rather rudimentary region locks, but unfortunately this also gives some people the idea that installing something like the SuperCIC mod chip to make a SNES region-free is easy. The patient that arrived on [Skawo]’s surgery table was one such victim, with the patient requiring immediate surgery to remove the botched installation before assessing the damage.

Here the good news was that the patient features the revision B CPU, making it a good console to rescue. The bad news was that the pads of the old CIC chip had been ripped up, there was a solder bridge on S-PPU1 between two pins and both the installed wiring and soldering were atrocious, requiring plenty of touch-ups.

With the CIC pads already a loss, finishing the SuperCIC mod seemed like a good plan, also since this would make for a nice region-free console. This mod involves a PIC16F630 with special firmware that works with the corresponding CIC IC in each cartridge, while also switching between 50/60 Hz mode to fit the cartridge’s region. After an initial test with PAL and NTSC cartridges everything seemed all right. Then [Skawo] ran the SuperNES Burn-In test from its cartridge, which gave dire news.

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