My new SAE 2600 power amp. Exploded

[turboyam]

... View As in Exploded View Hahhaah! got ya!.

Just bought it, it was sitting on the doc o the Bay. The seller mentioned that
the amp is powering-up but no sound. I will post later on what i found in there
till now.

 

[turboyam]

I payed a good chunk of money for it but my gut feeling was telling me that it
did not suffer a miserable life. It was in a rack, in a quiet home and had a single owner. There are 2 very small scratches on the handles that will disapear
with a touch of paint brush.
Some corrosion on handle screws, and fan aluminum housing was telling me that it was in a humid (or salty air) as it is from California, so i decided to take
it apart and clean it up. Checked all connectors, and pins for signs of corrosion.
So far, i found one blown fuse on the - side... The protection circuit has been modified, probably for the known PUP, too slow opening of the relays?.
The tech removed 2 pins (the ones closest to the 4 caps).
He added a 10uf 250v cap, a diode and a jumper (red) under the board.
There also is a red wire that enters the board, that's connected to one AC terminal on the rectifier...

I took the covers off the relays, cleaned the contacts (they were very slightly pitted). Did not test the relays coils yet, will do.

One of the BC307B transistors on the main board is acting, i plan on changing all six. (i tested them in circuit with a diode test multimeter).
All of the outputs are original SAE marked 11-0068 and 11-0074 and all test good on the multimeter.

On the pre-driver boards, there is a pair of SAE, one Motorola and one RCA on each, and the driver boards, one channel has 4 RCA's and the other board has 4 SAE,s, all of those in TO-66.
I will order all the caps for it except for the PSU ones for now, recap it and reassemble it and dim bulb test. Will change the 4 trim pots for Bourns too.

I did not check how i'll be able to adjust the 2 pots on the main board tho?.
It doesn't look like it's feasable without major thinking!?.
Here's the protection board picts:

 

[mjstriker5]

Check out my thread I made for my 2600 to figure out the pot adjustments. I think it was mentioned there. If not I'll dig around and find the forum threads I used to make measurements. The tough one is actually the pot on the output board. I have all that info though somewhere.

I would definitely recommend replacing the big wattage resistors as they probably are a bit worn. Or they might not be that bad of the unit hasn't seen road use. Mine definitely did and all those resistors were fried.

I'll also double check those transistors you mention and get you the replacements I used.

The relay board definitely has the mod to improve the relay. This amp is notorious for quick turn on and very slow turn off.

I'll also upload my BOM from mouser so you can look at the parts I replaced.

Good luck

 

[mjstriker5]

Double post.

 

[mjstriker5]

Here are some threads I used.

SAE 2600 restoration/recap.....need assistance. | Page 5 | Audiokarma Home Audio Stereo Discussion Forums

tarature quiescenza e bias su finale sae 2600

I'll try to figure out the exact process I used as it has been a few months. And I think there is another thread I used that was really helpful but can't recall off hand. I'll see what I can figure out and let you know.

 

[turboyam]

Check out my thread I made for my 2600 to figure out the pot adjustments. I think it was mentioned there. If not I'll dig around and find the forum threads I used to make measurements. The tough one is actually the pot on the output board. I have all that info though somewhere.

I would definitely recommend replacing the big wattage resistors as they probably are a bit worn. Or they might not be that bad of the unit hasn't seen road use. Mine definitely did and all those resistors were fried.

I'll also double check those transistors you mention and get you the replacements I used.

The relay board definitely has the mod to improve the relay. This amp is notorious for quick turn on and very slow turn off.

I'll also upload my BOM from mouser so you can look at the parts I replaced.

Good luck

Those resistors you are talking about are the ones on the driver boards? (the
5 watts ones), or the ceramic ones on the main board?.
As for adjusting the main board trims, i made 2 access holes in the amp's bottom chassis cover. I will use a long plastic screw driver 🙂.
I had found the other thread on AK too 🙂.
Thanks for your help! very appreciated!.

 

[turboyam]

Here are some threads I used.

SAE 2600 restoration/recap.....need assistance. | Page 5 | Audiokarma Home Audio Stereo Discussion Forums

tarature quiescenza e bias su finale sae 2600

I'll try to figure out the exact process I used as it has been a few months. And I think there is another thread I used that was really helpful but can't recall off hand. I'll see what I can figure out and let you know.

Hi. Did you have time to check on those things?.I got all of the caps from Digikey today, along with the Bourns and rectifier 🙂.

 

[doum]

Hello




I'm searching for a SAE 2600 complete service manual.
I dismounted one but I forgot the location of screws and spacers.😡
I can not find pictures to help me for winding.
Have you got an exploded view or a complete service manual with all parts listing and view?

Best regards

 

[llwhtt]

In my experience none of the SAE manuals were that complete. I've never seen an exploded view of any SAE amp, just schematics, parts lists, adjustments, views of PCBs and maybe some circuit theory.

Craig

 

[doum]

Ok, thank you.

I think I will succeed without, I began by sorting the screws and spacers.

 

[llwhtt]

I just got a 2600 in for repair, what a mess. I hope somebody didn't quit their day job!!! It's fully exploded now, I don't there was one screw that was tight while I was exploding it. My Mouser shopping cart is going to be filled pretty well after I get done ordering parts for it. The only a major bummer is one bad filter capacitor, have to replace all four them now, 10,000uf @ 120VDC, not much to choose from these days. Fun, fun, fun!!!!!

All of this in trade for a semi dead SUMO NINE. It's already been troubleshot and repaired.

Craig

 

[mjstriker5]

I just got a 2600 in for repair, what a mess. I hope somebody didn't quit their day job!!! It's fully exploded now, I don't there was one screw that was tight while I was exploding it. My Mouser shopping cart is going to be filled pretty well after I get done ordering parts for it. The only a major bummer is one bad filter capacitor, have to replace all four them now, 10,000uf @ 120VDC, not much to choose from these days. Fun, fun, fun!!!!!

All of this in trade for a semi dead SUMO NINE. It's already been troubleshot and repaired.

Craig

If all the outputs and driver transistors are fine, then having to replace the filter caps is not too bad. When I repaired mine I had to get creative replacing some of those driver transistors as the case type had changed. They are some awesome amps though and you can't beat those meters!!

Did you pick up a sumo nine regular or plus? I have been wanting to get my hands on one of those for a while. Had a line on a broken one but I think it has fallen dead in the water. Heard they are a pain to work on? I am curious to know what was wrong with yours and how difficult it was to get parts?

Thanks

 

[llwhtt]

With all of the previous crappy repairs I'm going to strip all of plug in boards and start over. Replace several parts on the mother board, mainly the bias circuit. I did notice upon disassembly that none of the bias tracking transistors were in contact with the heatsink, I'm surprised it didn't damage the output stage. Still the filter capacitors are the only bummer, $60 a pop.

I got a Gold NINE in return. One bad bridge rectifier, replaced all four. The right channel's "selected" LF353 was bad, the output clipped at around 20 Watts. I'm going to install my last two OPA2604s in it today. Also I'll order some LF412As as they'll handle the +/- 20VDC power supplies, that what the NINE+ uses.

Craig