SPX90: help IDing parts.

[MrMesh]

Hey all, I've recently acquired an SPX90 that's in a fairly bad way. I've ordered some new caps to do the recap that everyone suggests, but I also need to ID a few more parts and can't make any sense of the service manual. Is anyone either able to help me figure out the parts list in the service manual or help ID the following:
-D6, D7, L4, L5, L6 on the PSU card (VA81410).
-the regulators on the AD card.

Many thanks in advance. Any help/advice is greatly appreciated!

 

[pvision]

IIRC the PSU is identical to that in the Rev 7 so it might be worth a cross-check

 

[Khron]

D6 and D7 will need to be ultrafast or Schottky rectifiers, since they're on the output of a switching power supply.  The filter capacitors next to them are, at least on the schematic, rated at 25V, so the diodes can be anything from 60V and up. The size (if not even markings) of the stock diodes should give some estimation of what current you're looking for, but worst-case, some 3A jobs should be fine.

L4, L5 and L6 have their values clearly marked (150uH for the first two, and 20uH for the latter). Not 100% sure it's worth looking for an exact match for the physical footprint though, but that's just me.

 

[fripholm]

-the regulators on the AD card.

In my unit, these are just standard +/-15V regulators for the analog part - 7815 and 7819 7915.

HTH

 

[radardoug]

In my unit, these are just standard +/-15V regulators for the analog part - 7815 and 7819.

HTH

Oops, dont you mean 7815 and 7915. Thinks, must view my post before submitting!

 

[MrMesh]

Thanks all, that's helped significantly!

For the diodes would a 1N4936 suffice? Was thinking of grabbing a couple of these:
https://www.mouser.de/ProductDetail/ON-Semiconductor/1N4936G?qs=sGAEpiMZZMtbRapU8LlZD9Yt6EMzPspSp%2FxcLB3anF0%3D

 

[fripholm]

Oops, dont you mean 7815 and 7915. Thinks, must view my post before submitting!

Absolutely, 7915 for the negative regulator. Sorry, post edited...  :-[

 

[Khron]

400V's a bit overkill, but the 1A is a "maybe" - might wanna compare with how "fat" the stock diodes are (or aren't).

Thanks all, that's helped significantly!

For the diodes would a 1N4936 suffice? Was thinking of grabbing a couple of these:
https://www.mouser.de/ProductDetail/ON-Semiconductor/1N4936G?qs=sGAEpiMZZMtbRapU8LlZD9Yt6EMzPspSp%2FxcLB3anF0%3D

 

[mobyd]

Beware the black (formerly yellow) glue on the PSU board of SPX90s. In the 30 years since the thing was made, it has decomposed to hydrochloric acid and eaten the legs off anything it has come in contact with, especially those little chokes.
M

 

[MrMesh]

Beware the black (formerly yellow) glue on the PSU board of SPX90s. In the 30 years since the thing was made, it has decomposed to hydrochloric acid and eaten the legs off anything it has come in contact with, especially those little chokes.
M

Ha, yep. I found this out the hard way. 

400V's a bit overkill, but the 1A is a "maybe" - might wanna compare with how "fat" the stock diodes are (or aren't).

Cheers. I'll take a look tomorrow. Should the amperage be higher or low?

 

[Khron]

You probably wouldn't wanna go with lower current rating than the stock ones.