cyrus 2

[rbphoto]

Hi chaps,

I'm hoping someone might be able to help diagnose a problem in a Cyrus II I've just acquired for um, shall we say, sod all. It's an early model, plastic case, push button, 8 output transistors.

The power amp seems fine, I'm sure alot of the caps should really be replaced given their age though.
The preamp section though is fairly knackered. There is a fried op amp in the RIAA-L section, OA5, and a blown cap at C68. The traces are blown between the white supply wire CT and capacitors C63 and C64, and also between X36 and D12.

Sadly this is about as far as my ability to diagnose the problem gets... but if someone could point me in the right direction, I reckon I am in with a fighting chance to get the amp back on form when I can get the parts. Of course chances are that the traces blowing are indicative of further, more serious issues.

I see that the schematic was posted earlier, but it's no longer online. If someone has it handy and could email it to rbphoto (at) gmail . com that would be tremendous!

Any other troubleshooting advice greatly appreciated, this would be only my second amp repair after a quad 303

Very helpful thread, this!

Cheers,

Rick.

 

[Colin66]

At the risk of asking a daft question ... is it possible to turn cyrus 1 into power amp - if so any clues as to how to go about it?
(having re-capped my old one thinking of using it to improve AV sound for front speakers)

Thanks

 

[Sonusthree]

At the risk of asking a daft question ... is it possible to turn cyrus 1 into power amp - if so any clues as to how to go about it?
(having re-capped my old one thinking of using it to improve AV sound for front speakers)

Thanks

I did it to mine by bypassing the volume control/switches and effectively wiring the RCA socket directly to R49 here:

http://www.tcaas.btinternet.co.uk/cyrus1pwr.gif

 

[richie00boy]

As there are no tone controls or other pre-amp type stuff to bypass, I would just turn the volume up full and job done.

 

[picturevalve]

Cyrus diagrams here :

Cyrus Diagrams, Schematics and Service Manuals for FREE

 

[Gonethesame]

Hi,

have to change the 470/6 FB caps on a cyrus one with muse kz, would like to know about polarity?

do you have some clues?

thx alot

 

[bleachershane]

Hi,

have to change the 470/6 FB caps on a cyrus one with muse kz, would like to know about polarity?

do you have some clues?

thx alot

I am currently refurbing a full Cyrus II and I'm just getting on to the capacitors you are at...

These capacitors are bipolar, as are a lot of the orange Elna capacitors in the phono stage of my Issue 07/TOG Cyrus II. I have managed to work out the polarity of all the phono stage bipolars to replace with Panasonic FMs but these two ROE 470uf 6V bipolars are proving a pain, I've yet to get a mate of mine to trace the polarity of them.

I have ordered Panasonic FMs for them, but also bought a couple of Nichicon Muse ES bipolar capacitors (470uF 16V) from a German seller on eBay.

If you're unsure of the polarity you could always replace them with bipolar capacitors, seeing as that's what they are...

 

[Gonethesame]

For me polarity is negative on the 1k resistor,

 

[a479]

Hello everyone,

(I'm a newbie on the forum, and hope to post "right"...)

I'm looking for a simple info about Cyrus II, but after a long search on the forum, I did'nt manage to get it...

So, I'm wondering about the value of the original balance potentiometer ?
As I have to supresse it, because of an accident...

I wish to fit an ALPS 10k volume pot, and replace balance pot by two resistor of the good value.

Thanks, by advence,
Antoine.

 

[a479]

Finally, I managed to measure my broken balance potentiometer. (it's much harder, without the legs !) It appear to be 47 K, so I must be fine with 2 resistors of nearly 25 K...

 

[AndrewT]

Do you need a balance adjustment?