[37mil]

Hi,
I need the ud-501 service manual, can someone help me?
Thank you

i’m familiar with the circuit. Is there anything specific you want to know?

 

[hans888]

Hi,
I got an used one, but is coming from japan, so at least will need to change the input voltage pin to 230v and would like to be sure which one it is. Apart from that, probably in the near future will upgrade some capacitors and maybe opamps since the good results reported here, that's why I think having the manual would be helful.

 

[37mil]

That's easy. Follow where the mains power goes through to the PCB (got that big filter on it) and there's three pairs of through holes for 3 different voltages. 100, 120, and 230V. Use 5mm jumper wire to bridge your desired voltage, and cut the 100V wire. Just look at the main PCB for any caps you want to change. The space is tight so you have to measure the diameters of the caps you want to replace else you will be using long wires to connect them to the board. The op amps are dip 8 and easily removable if you have experience - just replace with a socket and you're good to go rolling. Be warned though, there's 6 dual op amps so it could be expensive if go discrete.

 

[37mil]

I’ve taken this from page one of this thread.
Red: audio output caps
Yellow: op amps
Blue: voltage regulator caps
Green: power reservoir/smoothing caps
Purple: pcb with jumper settings

as it’s a dual mono design, it costs twice as much to change anything. The pics only show one channel.

 

[hans888]

Thanks a lot, this was a big help.
Will test the dac for a few weeks and surely will come back for advise on the more critical upgrades, because changing all those components is too much.... Had already read (a bit) and was thinking about switching the 4 output caps for something nice and a couple of burson v5 (one per channel) to start with, but who knows, maybe I'll fall for the dac as it comes...
Again, thank you.

 

[hans888]

Ok, the jumper is already changed to 230v. Leave a pic for reference, since others asked before I did.

Btw, the "mini-transformer?" (I don't know what exactly it is) which is besides, rated 100V, is it ok to leave it like that?

 

[37mil]

I don’t know what that is. Didn’t realise there was a transformer there. That could be a show stopper. I’m pretty sure the jumper settings only change the windings to the main torroids.

you might have to buy a part from teac.

 

[hodgjy]

Why not just get something like this or equivalent?

https://voltage-converter-transform...nsformer-with-usa-plug-5000-watt-ce-certified

 

[hans888]

Well, I'd like to run it at 230v. I thought it was possible with just the jumper thing, but maybe I was wrong.
I attach a couple of pics more. Looks like a transformer, 5 pins per side. Part number E018639-00A PESB-T100V TAM K 1322. Haven't found any info on the net so far...

 

[hans888]

And the thing is that there are two of those frransformers, one for 100v and another for 220v. Bad news

 

[37mil]

try ordering that part from teac? what does it do, btw?

 

[hans888]

try ordering that part from teac? what does it do, btw?

I think it’s a dedicated transformer just for the standby mode operation. Strange because this device has no remote.

I still didn’t dare to switch it on...

 

[hodgjy]

I think it’s a dedicated transformer just for the standby mode operation. Strange because this device has no remote.

I still didn’t dare to switch it on...

From the specs I read, it seems like it has a power saving mode, so one of the transformers, as you said, is likely there for standby mode and wake up.

Another thought is they're not transformers at all but chokes.

 

[manishex]

I only use the UD501 as a DAC, which op-amps should I replace? I have some spare Bursons v5i's duals lying around, would it make much difference? Anything else I can easily do?

 

[hans888]

Yes Jay, choke or transformer or HF filter, these devices look almost the same from the outside. And my knowledge in electronics is very limited...
I'm pretty sure Teac wont sell just this piece alone, I would need to order the whole STBY PCB and wont be cheap.
I've been examining the little thing a bit and it has some words engraved at the sticker's opposite side...
E28-3PD3/12
8HG35
I think E28 its the type of transformer, 12 the output dc voltage and 35 the watts. But just a guess.
Apart from that I had some succes on the net finding this...





So it looks that I would toast it if I plug it at 230v...