MrMesh

SPX90: help IDing parts.
« on: March 15, 2020, 05:04:58 PM »
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

Re: SPX90: help IDing parts.
« Reply #1 on: March 15, 2020, 06:40:26 PM »
IIRC the PSU is identical to that in the Rev 7 so it might be worth a cross-check

Khron

Re: SPX90: help IDing parts.
« Reply #2 on: March 16, 2020, 11:24:51 AM »
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.
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

fripholm

Re: SPX90: help IDing parts.
« Reply #3 on: March 16, 2020, 02:34:15 PM »
-the regulators on the AD card.

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

HTH
« Last Edit: March 17, 2020, 05:00:43 AM by fripholm »

radardoug

Re: SPX90: help IDing parts.
« Reply #4 on: March 16, 2020, 04:21:44 PM »
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

Re: SPX90: help IDing parts.
« Reply #5 on: March 16, 2020, 05:45:11 PM »
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

Re: SPX90: help IDing parts.
« Reply #6 on: March 17, 2020, 04:59:55 AM »
Oops, dont you mean 7815 and 7915. Thinks, must view my post before submitting!

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

Khron

Re: SPX90: help IDing parts.
« Reply #7 on: March 17, 2020, 10:53:43 AM »
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
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

mobyd

Re: SPX90: help IDing parts.
« Reply #8 on: March 17, 2020, 03:01:38 PM »
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

Re: SPX90: help IDing parts.
« Reply #9 on: March 17, 2020, 06:10:28 PM »
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.  :o

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

Re: SPX90: help IDing parts.
« Reply #10 on: March 18, 2020, 10:33:41 AM »
You probably wouldn't wanna go with lower current rating than the stock ones.
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans


 

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