Marantz SA-KI Pearl Lite REPAIR

[rhiollyrubgt]

Hi,


I've just bought this player in a faulty state. It doesn't turn on.


I've done some simple tests and narrowed it down to the mini transformer - 00D2336615002 It's primary is open circuit. There's also a mini 1.25A fuse which is blown.



I've looked at the service manual but it shows very little in terms of helping me replace the transformer. Where can I get a replacement from?



Any help would be greatly appreciated.


Thanks

 

[Mooly]

Have you tried anything with this?

It might be possible to use a small centre tapped block type as replacement. We can make assumptions. C884 is rated at 16V and so will perhaps run at anything up to 12 volts DC.

That sets a possible value of 9 volt AC for winding 7-8.

The upper winding looks to feed just the relay and that would then be 18V AC giving 25 volts DC.... which happens to be the rating of C804. So a bit marginal but in the right ballpark.

An 8-0-8 type perhaps. It doesn't look critical. Perhaps even a 6-0-6 would suffice and at light loading a 6-0-6 would be around 15% higher anyway.

Measure the dimensions of yours to get an idea of VA rating. Weight is a good guide as well. There are loads of small transformers around.

Try it

This kind of thing:
https://cpc.farnell.com/block/vb1-5-2-6/transformer-1-5va-2-x-6v/dp/TF01238

 

[rhiollyrubgt]

Thanks Mooly, I'll look into it. Not tried anything yet, just did some simple tests to determine the problem.

 

[rhiollyrubgt]

Sorry for being a bit of a dummy but, taking the transformer you suggested... It has 4 output pins while the original has 3. How would I go about fitting it?

 

[stvnharr]

Have you considered sending the player to a Marantz Service Center?
Marantz uses proprietary transformers so if the transformer is indeed faulty you will likely only be able to get it from Marantz and only if they service the player.

 

[Mooly]

You would have to join the two individual secondaries in series to form a 6-0-6 transformer by connecting two middle pins.

That would give you three connections. Either outer terminal would then become '8' on the diagram, the middle connection '7' and the other outer would be '6'.

So the AC voltage measured from '8' would be six volts AC on '7' and twelve volts AC on '6'.

You should also check that ALL the diodes connected to that transformer are OK and that non are short circuit. Why did it fail in the first place.

Ultimately you have to be prepared to experiment. You could also try powering that section from a DC supply as a test (say 9 volts DC across C884) and checking that the stabilised output from the regulator is OK. Even a PP3 might be OK for that.

Assuming that was OK, you would then have to either momentarily short the relay to get the player to fire up, or apply another DC voltage across C804. The voltage across C804 is just used to initially kick the relay on, after that the stabilised supplies keep it power.

Three PP3's might get you a working player as a test. One for the input to the reg, and two series connected ones to give 18 volt across C804.

 

[rhiollyrubgt]

Thanks for the help, Mooly but I think I'm beat, well for now anyway.

I tested the diodes around that area and it seems quite a few have failed. I'm right in thinking that I can test in circuit and there should be a measurement one way and nothing the other? Well about 4 of them have measurements both ways.
I thought it might be a case of a surge or something knocking the isolation transformer and fuse out but I think this needs a pro to go over the whole board.

Thanks for the help anyway, you've been great.

 

[Mooly]

You can't read them in circuit because of the interaction with other components. There's a good chance that unless any read short circuit (or really low ohms, say a constant 100 ohm or lower) that they are going to be OK.

Thermal fuses can and do fail in transformers for no obvious reasons.

 

[rhiollyrubgt]

Thanks Mooly, just awaiting delivery of the transformer.

 

[Mooly]

then.