Replacing Power LED on MicroVAX 3100/95 Power Supply

Maciej W. Rozycki macro at
Tue May 12 20:40:59 CDT 2020

On Sun, 10 May 2020, Peter Coghlan via cctalk wrote:

> > I seem to remember people saying it is quite difficult to replace these,
> > mainly because you can't get them out without breaking the holder. Is that
> > right? Has anyone done this successfully and have any tips?
> Is this the green LED in a H7821 PSU? I managed to get one out of the holder
> with a bit of difficulty before I realised I could have left it in place and
> the board can just about get past it when the plug at the far end of the leads
> feeding it is plugged out from the board.

 If the holder is the same as with the H7826 PSU, then it's a generic part 
still manufactured.  I bought whatever was the minimum quantity sold by 
Farnell when I broke one along with the LED a few years ago.  I still have 
a few available and I could post one set once I am back to my UK home 
(which is given the current situation regrettably not going to happen 
anytime soon).  Otherwise you can order it yourself: 

> > Are there any recommendations for a replacement? If I remember correctly the
> > LEDs used in those days were not as bright as modern ones and a modern one
> > would end up being much brighter because of the higher voltage maybe?
> Maybe it would be possible to tack blobs of solder onto what's left of the
> leads on the original and use them to attach fine leads, digging out a small
> amount of the LED casing around the leads if necessary?

 I chose an LED matching the original colour, also of the case, as closely 
as possible: 
<>, but 
still haven't installed it (well, ahem, I need to fix the PSU itself 
first), so I can't comment on the result.  I could post one of those along 
with the holder if needed (subject to the condition noted above).

 An LED will dim with use, so you may not be able to closely match a worn 
one with a brand new part, but I suppose you don't actually need to be 
*that* exact with your equipment, do you?  Otherwise you can always put a 
resistor in series to dim the light produced.



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