exxos's Atari, Amiga & retro forum

Yeah, I was surprised that the flyback transformer unit and the capacitor unit are actually separate too. They're usually in a single plastic can.

Well, the monitor stopped working again, so I took the PCB out and had a look at the socket pins...


Erm, every one of them had cracked/broken!

Resoldered, after getting rid of the manky solder and soaked the board in IPA as the solder side was absolutely full of old flux.

Anyway, I've put it back together and it's not working. It sounds as if it's building up a charge and then discharging. It's quite possibly residual IPA so I'm going to leave it for a while.

:shock: If you have a higher resolution shot, maybe you could post this in the electronics area as a example of dry joints :)

Actually, the sound was a red herring, sort off.

The HT coil was powering up and discharging BUT it wasn't a fault with the monitor...

I was using the new power supply I'd bought which is rated at 18V DC, 1.32A. The monitor draws between 1.08 and 1.2 amps, steady state.

However, when starting up it *very* briefly draws a lot more and the new PSU just can't cope. The voltage collapses to effectively zero and then reenergises up to about 9V before collapsing again.

Powering the monitor using the bench power supply works perfectly.

I'm guessing that I may need a 3A PSU just to cope with the start-up current.

@stephen_usher does your bench psu allow you to throttle total current? That might help with determining load or using a clamp meter perhaps but you might miss the blip of the peak load.

Yes it does. I've currently got it at 1.3A, but the voltage only drops a couple of volts at start-up and then recovers within less than a second.

Anyway, with the bench PSU...

exxos wrote: 14 Jul 2021 21:14 :shock: If you have a higher resolution shot, maybe you could post this in the electronics area as a example of dry joints :)

That's the full resolution I'm afraid The iPhone was on 2x magnification mode and as close as i could get so that it could focus.

I increased the maximum current to 5A and turned on the over current protection... The PSU cut out.

So there must be a very brief surge current. I'm guessing that adding in a large inductor could help with this as it would dampen the surge.

The new PCBs are out for delivery! *Yay!*

I'm not in work today and they're being delivered there. *Boo!*

stephen_usher wrote: 15 Jul 2021 09:52 The new PCBs are out for delivery! *Yay!*

I'm not in work today and they're being delivered there. *Boo!*

Don't you just hate it when that happens!!