CTM640/644 component Help!

[pledg]

Hi,


I need to replace a failed D510 on a CTM640 monitor it's listed as SR2M Zener Diode on the parts list.


Is there a modern equivalent part?


Would an R2KY be a good replacement? or an UF2002


Thanks


Pledg

[Bryce]

Are you really, really sure that the diode has failed? That's a 130V Zener diode, which is not only extremely difficult to destroy, but also can't be measured / tested like a normal diode. How have you confirmed that it's damaged?

Bryce.

[pledg]

Absolutely right Bryce apologies I was having brain fade...

[darkhalf]

@Bryce unfortunately might have to reopen the question from @plegd since I have two monitor boards here. One of them the SR2M measures forward voltage fine (yes to test reverse clip voltage would need > 130V). The other is short both ways, so completely dead

Looks like a common failed part since Donberg stocks them (I just bought several replacement flybacks... which I knew this earlier)
https://www.donberg.co.uk/catalogue/sr_2m.html

Is there an equivalent which I can get from digikey etc that you might know of?

[Bryce]

Not from Digikey, but there are quite a few sources for the SR2M is you do a search. But I'd be curious to know what is killing them?

Donberg doesn't stock anything. They are a reseller.

Bryce.

Edit: More local? http://albury.net.au/~allfix/catalogs/semi.htm (listed as R2M)

[darkhalf]

@Bryce I had ordered the CTM644 (30EUR) and an Amiga 1081 monitor (80EUR!) flyback from Donberg. They took about a month to arrive. Some other places had CTM640/CTM644 limited stock about 20EUR

Can confirm it is the flyback dying, shorting out and then killing the diode amongst other components all the way back to the fuse. Main parts affected are diodes and fusable resistors. However the voltage regulator also gets damaged. I've documented what I've found from both monitors here:
https://www.cpcwiki.eu/forum/hardware-related/ctm-640-colour-monitor-repair/new/#new

Unfortunately that R2M link didn't work for me, so I'll keep looking for SR 2M or equivalents in the meantime for the CTM640

I've got a white flickering screen now. So did the same as we did with my friends 1084 replacement we had to dial back the brightness (screen) on the flyback. When that died it only took out the driver transistor, so was an easy job compared to this.

For this one and I suspect other components damaged, since no display on there. Apart from checking voltages on the LM7800 I'm not sure where to look next
 

[darkhalf]

Donberg listed: SR 2M AVALANCHE PROTECTION DIODE 130V / 1A = 
SR6NA (no results)  

MATSUI 1440A (obsolete)

R2KY REF D508 
https://www.wagneronline.com.au/diodes/semiconductors/electronic-components/r2ky-3635/625/pd/
Listed as 130V protection diode