One heck of a hack

[salvogendut]

The other day it almost felt like I had hit the jackpot. I found this dude on Facebook who was selling the following : 1 CTM640 + 1 MP-3 + 1 DD1 + 1 FD1 + 1 464 for ... drumroll: 100 euros. After a bit of back and forth I pressured him a bit to close the deal and soon after it was done, 150 Euros including shipping. Seemed like a dream deal. However the status of everything was 'unknown' so I told the guy don't worry I'm aware of it and I am gonna take care of any fixing that will be necessary. Once everything arrived home and I unpacked everything I could not believe my eyes. 


The first thing that I checked was the monitor. I turned it on and there was no signal but it buzzed and whirred as if there was some activity. Luckily I had the wits to test the output of the dongle connector before I hooked up anything to it: 13+ Volts. Hang on! This can't be right. I checked again and again and quickly realized there was something odd in the monitor so I put it aside for the time being.

After I checked the 464 and DD1/FD1 everything was luckily ok (except for the drive belt, but that seems to be an easy fix).

Now going back to the monitor that's when I started noticing the oddness of it. Somebody had drilled a hole in the front , in the middle of the logo and they also had managed to screw some bolt on one of the sides.. what the heck!? 





So I opened it and that's when I stood still and awestruck: What the hell is that? And what is that for? It was bolted onto the side of the monitor case and the cables together with a small pcb were tucked in inside.



I managed to remove that by unplugging the black electric connector and cutting a couple of thin wires which connected it to some other cables on the motherboard. And it looks like this when it's out of the monitor:










Now that I removed it, the monitor won't power on anymore and it seems like whatever this thing is was feeding or re-feeding power to the monitor, so I will try to reconnect it to make some tests.

It occurred to me that the MP-3 tv tuner has one socket that accepts 12V in input and that is maybe why this thing was outputting 12+ volts. Is it possible that they had turned the monitor into just a tv with this hack? Or would this be some hack to fix it somehow because it was not powering on anymore? I have absolutely no idea what this thing is. Any ideas ? Any tips?

[eto]

Is the 12V connector also a 5.5mm/2.1mm plug? If yes and if GND is on the inner pin it might have been a mod to use the CTM 640 with a 664 or 6128.

Btw: even with a malfunction monitor this was a great deal. 

[salvogendut]

Is the 12V connector also a 5.5mm/2.1mm plug? If yes and if GND is on the inner pin it might have been a mod to use the CTM 640 with a 664 or 6128.

Btw: even with a malfunction monitor this was a great deal.

No it was the regular plug that would go into a 464/6128 5V and the inner pin is positive. When I connected it to the femal connector of the MP-3 tv tuner I could see the MP-3 led turn on. They might have modded it , together with the other stuff.

Just a thought, I can see the transformer that was bolted to the case has a fuse in it. Is it possible that somehow they were using that thing in place of the original transformer/PSU (which may be toast) ?

[salvogendut]

Ok a little update: this hack was apparently just a transformer added to the main power input so that it could spit out 12V on the (originally 5V) connector that was supposed to go into the computer. The reason why they did this is unknown (I am thinking they wanted to power the MP-3 out of the monitor directly) but whatever. However this thing might have fallen at some point and the transformer was barely attached to the case, its cables and its PCB were loose inside the space so they may have caused some shorts or worse. I just removed it and also removed the mobo and gave it a good clean. However if I turn it on there is nothing going on. No signs of life on screen and 0 volt from the CPC connector. If anybody with some experience wants to give me some tips how to go about to checking what's failed I'd appreciate. I have never repaired a monitor.

[BSC]

I have no experience, just happened to come across that thread, so just one word of warning (you might already know it): Tubes are pretty dangerous to work on. I'll just cite ChatCPT because it's 2025 (my concerns were mainly related to point 1):

CRTs (cathode-ray tube displays, like old TVs and monitors) can be dangerous to open for a few reasons, mainly related to stored electrical energy, fragile glass, and toxic materials:

• High Voltage Stored Charge
  
  • CRTs operate at very high voltages, often 20,000–30,000 volts (sometimes more).
  • Even when unplugged, the large capacitors and especially the anode of the picture tube can hold a dangerous charge for days or weeks.
  • Accidentally discharging this voltage into yourself can cause severe electric shock, burns, or even be fatal.
• Implosion Hazard
  
  • The tube is a big glass vacuum chamber.
  • If cracked or damaged, it can implode, sending glass shards flying at high speed.
  • Manufacturers often reinforced CRTs, but the risk is still real, especially if handled carelessly.
• Toxic Materials
  
  • CRT glass contains lead and sometimes other heavy metals.
  • The fluorescent coating inside the screen can contain phosphors and toxic dust.
  • Breaking the tube can expose you to hazardous materials.
• Sharp Internal Components
  
  • The inside often has sharp metal edges and fragile wiring that can cut or puncture skin.

[salvogendut]

Thanks @BSC you did the right thing to remind folks that there is no joking when handling CRT tubes. I did my own research before actually touching anything and I took all the precautions and discharged the CRT anode properly (although I think this monitor has not been powered on in ages and it seemed pretty empty of any residual voltage)