Replacing Power LED on MicroVAX 3100/95 Power Supply

Nigel Johnson nw.johnson at
Wed May 13 05:29:38 CDT 2020

If all you need it that little mounting collet, I have a dozen or so of 
them somewhere for the price of postage from Canada!



On 13/05/2020 02:23, Rob Jarratt via cctalk wrote:
> That's fantastic Maciej! I often buy from Farnell, so there is no issue with
> getting those parts myself. When I have accumulated enough wants to warrant
> an order I will get them.
> Regards
> Rob
>> -----Original Message-----
>> From: cctalk <cctalk-bounces at> On Behalf Of Maciej W.
> Rozycki
>> via cctalk
>> Sent: 13 May 2020 02:41
>> To: Peter Coghlan <cctalk at>; General Discussion: On-Topic
>> and Off-Topic Posts <cctalk at>
>> Subject: Re: Replacing Power LED on MicroVAX 3100/95 Power Supply
>> 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:
>> <
>> 5mm-led/dp/8576378>.
>>>> 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.
>>   HTH,
>>    Maciej


Nigel Johnson

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