Repair Cyrus dAD7

I'm looking for the service manual to repair the dAD7. Unfortunately, it appears that someone else has been poking in it and it's no longer original 😔. Perhaps someone can have a look at the photo to see if modifications are reversible. The CD player only plays the last two tracks and makes a terrible noise when trying to play the other ones (hard clang).
 

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Cyrus was so kind to send me the service manual so I can start repairing 😃. Some of the solder pads are missing and I was wondering if someone knows how to fix that properly. In particular C136 appears to be challenging as there are no pads at the front and only one at the back.
 

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Joined 2002
No I meant to use the (iron, oh oh) lead wires used as (now insulated) PCB tracks.

No traces to … certain points. I hope that those points (hint: read schematics) can be reached with the new caps uncut lead wires that identify themselves as PCB tracks.

Simple, proven and effective.
 
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You need a schematic to know where for instance C139 goes. Not traces but connection points. The cap only has 2 lead wires so there will be 2 points where this cap connects to with a + and a -. For instance decoupling the positive power supply of an opamp. Then you can now connect the + of the new elco to that opamps positive supply pin thereby ignoring the original but damaged PCB trace to the cap. The - in this example to GND. Just an example for explanation! If this simple job is too much then please do not bother and leave it to someone that does know how to do this.

With C136 you don't need to know traces either. You use the existing PCB holes and connect the long wires to the points where the cap was connected to. Think function of the cap not how it was situated on a perfectly fine PCB, you have no choice but to repair. The shorter the wire can be the better it is so the challenge is to make it as good as possible.

RISK: unexperienced will lead to thinking errors especially with decoupling caps of a negative power supply line (dual/symmetric PSU so +/-12V or the like) where the + of the cap is connected to a GND point. Its - is then connected to the opamps - pin. The mind says to connect the + of an elco to opamps pins somehow -> thought defect.

* Think, act, check and verify again. Show pictures before switching it on and explain what you have done beforehand. Many members can assist.
 
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Thanks for your explanation. It's merely that I can't see where it connects to (front nor back) on the PCB where C139A's connection to the traces is clearly visible. The backside has a screen, so I expect it connects under the screen in parallel.
 

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Last time: thought defect is to think of "visible" and "traces". You need to know the connection points by reading the schematic! C136 its + goes to pin 20 of IC102. It's - to a GND point, the same GND where C140 and C140a are connected to. Verify with DMM and help from mr. Ohm which side is GND. Connect - of new C136 to that point. Simple.

BTW I think I have seen the device before. Does it have a low jitter clock by Audiocom? The desire to reverse mods and make it "original" (why?) may have been the cause for the defects you are now having. C136 was still intact and so were its traces on the first picture. First find a cause for the defect, then repair and only then one can think of reversing good modifications in another thought defect that original is better. Do you have a good soldering tool, desoldering braid and 60/40?
 
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On second thoughts (these Cyrus devices are old) it may very well be that the in your eyes non-original mods are done by Cyrus :D In the heydays of audio by the British cottage industry modifications were not unusual. No one likes to get 100 CD players back for checkups.

So focus on repair and only then of side steps that don't add anything. Make problems smaller and not larger.
 
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There is no external clock, only what you can see in the photos (unless they only swapped the crystal). I bought it as 'defective', not knowing that it had been modified. The CD player reads the TOC perfectly, and depending on the CD, it's possible to play some songs. I have only listened to it on an external DAC and it sounds pretty good.

The majority of the times it didn't play any songs and made loud clicks (disc spins up and down).

When I asked the seller about the modification, he mentioned that he had bought it like that and it worked before he put it in storage. He had taken it it for repair to Sound Gallery (hi-fi shop in Groningen) to see if there was a problem with the laser. They had switched in another mechanism, but the CD player was unstable, so they switched the mechanism back.

The bizarre thing is that, according to the service manual, the dAD7 should come with a CDM9/60 Pro, however mine has the CDM9/44. I know that the CDM9 Pro has a brushless motor and was wondering if the voltage is different compared to the 44.
 

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It's also possible that Cyrus did adapt the control electronics to the 44 if there was a shortage in supply of Pro.

Might look for a donor dAD7, as I like the design and am still playing CDs. (Though streaming with Audirvana via Macbook pro to Topping V70 Velvet DAC sounds great 😃)
 
I can see that on this Cyrus the CDM9 drive control card is directly integrated into the motherboard.
You can already try to replace C139, which is not too complicated, and then replace the two tantalums at the foot of the TCA0372DP2 to see if it is better or not and perhaps prepare yourself mentally to replace the TCA itself.
 
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