I am still having fun L trying to resurrect a Cyrus III amplifier. I have now established that the fault lies on the pre amp input board, but now it gets tricky.
Does anyone out there have a service manual for this unit?
Thanks
Guillaume
Does anyone out there have a service manual for this unit?
Thanks
Guillaume
I'm fixing my mates Cyrus 2. Bought a service manual from Cyrus for £18. www.cyrusaudio.com I think, but the last 2 emails I sent them I got no reply...
The manual is not all that great, but at least I've got schematics to work from now.
The manual is not all that great, but at least I've got schematics to work from now.
I know about the manual from Cyrus, I sent an e mail some time ago and they offered the manual for GBP 17.55 or so. I did not order then. Since thenm I have tried again and have received no reply at all.......
Their response to my PSXR to standalone use question was a little patronising as well.....
Rgds
Their response to my PSXR to standalone use question was a little patronising as well.....
Rgds
Yes, I was annoyed that they didn't reply to my emails as well, especially as I was asking to buy parts from them!
What was your question on the PSX - I may be able to help. In fact I was thinking about using the PSX and building my mate a new amp to go with it.
What was your question on the PSX - I may be able to help. In fact I was thinking about using the PSX and building my mate a new amp to go with it.
I just wanted to revert the unit to normal non PSX operation, I did get a reply to that query on this forum already. I also just got an e mail from Cyrus, GBP17.55 for a service manual or GBP72.00 for a new input board.
G
G
Guillaume
Please pardon my ignorance but how complex is that board? Can you post pics? I have a strong feeling that we'll fix it without a service manual.
Please pardon my ignorance but how complex is that board? Can you post pics? I have a strong feeling that we'll fix it without a service manual.
I believed so 2 Peter....
I do not own a digital camera and probably never will.... then again I do own a CD player for convenience and availability of music so maybe when they get even cheaper and nastier....
The Cyrus 3 is microprocessor controlled for input switching and volume control. The input board I believe includes pre amp, volume and RIAA as well as psu for these. Only the PSU components are not surface mount. The various digital/analolog switches and op amps are surfacemount. If they were not I would spend ZAR100 / USD 15 on some parts and replace all semis.
I am going to buy the manual, me and a buddy have spent 2 many hours already........
The real problem is that as long as there is a fault the amp shuts down making any testing/measurement seriousy tough.
I do not own a digital camera and probably never will.... then again I do own a CD player for convenience and availability of music so maybe when they get even cheaper and nastier....
The Cyrus 3 is microprocessor controlled for input switching and volume control. The input board I believe includes pre amp, volume and RIAA as well as psu for these. Only the PSU components are not surface mount. The various digital/analolog switches and op amps are surfacemount. If they were not I would spend ZAR100 / USD 15 on some parts and replace all semis.
I am going to buy the manual, me and a buddy have spent 2 many hours already........
The real problem is that as long as there is a fault the amp shuts down making any testing/measurement seriousy tough.
I tried to get a service manual for Cyrus III and was told to send the unit in.I have a faulty one aswell and beleve it is the pre board but that micropro makes it hard to test.If you get a manual tell me how much for a photocopy and i will pay PLEASE.
Authorized service
Hi All,
I do authorized service for this brand. I don't have a scanner but perhaps we can talk it through.
The protection circuits can confuse you, sometimes the failure is there.
Guillaume, I haven't seen a fault on that board yet, so this is a first. I use a longer flex cable so I can flip everything apart to troubleshoot. A question. Why do you think the fault is on the preamp PCB assy? I just need to start somewhere here.
-Chris
Hi All,
I do authorized service for this brand. I don't have a scanner but perhaps we can talk it through.
The protection circuits can confuse you, sometimes the failure is there.
Guillaume, I haven't seen a fault on that board yet, so this is a first. I use a longer flex cable so I can flip everything apart to troubleshoot. A question. Why do you think the fault is on the preamp PCB assy? I just need to start somewhere here.
-Chris
I am guessing at the fault.It is dead.No lights.
I have checked to see if the power amp and pre amp boards have power and they do.So I thought the mPro might be failing????
I have checked to see if the power amp and pre amp boards have power and they do.So I thought the mPro might be failing????
Kieranphillips
Is your unit set up for the PSX or no? Check to make sure the flex pcb to the front panel is properly seated. Do you have +5V on the 7805 on the control pcb? Should be around +8V in to the reg ic.
When the unit is first plugged in, what happens on the front panel, if anything? I've not seen the uP go on these unless hit by a surge.
-Chris
Is your unit set up for the PSX or no? Check to make sure the flex pcb to the front panel is properly seated. Do you have +5V on the 7805 on the control pcb? Should be around +8V in to the reg ic.
When the unit is first plugged in, what happens on the front panel, if anything? I've not seen the uP go on these unless hit by a surge.
-Chris
Okay, check for +8 to 10V in to the control PCB at the front and +5V out of the 7805 regulator & pin 1 uP. Then, if that checks, see if you have oscillation on pins 2 & 3 of the uP. Also check C306, that's 2.2mF for shorts. That would take pin 6 on the uP down (reset). You can 'scope the buttons for key scan as well. Check if one is shorted or stuck down.
Let me know what the results are & good luck
-Chris
Let me know what the results are & good luck
-Chris
I am back, thought this thread had died....
Hi
I did actually get a service manual for this unit, it is a fairly wicked thick document. I am in South Africa so photo copies may be a nuisance. Maybe scanning and zipping is better. I will see what I can do. The stuff is with a friend though so please give me a little time, a week or so.
The reason I thought the pre amp section on mine is faulty is that it goes through a set up sequence and then flashes the power LED indicating a fault according to the manual. The moment the ribbon from the pre amplifier is disconnected this fault indication dissappears.
All of the output transistors appear fine and I think supply rails 2. Their to regulator stepped supply is a little confusing though. It is very diffycult to fault find this unit as it does not power up to allow me to inject a signal and trace what is happening.
Any advice on typical faults on these units to give closer look would be highly welcome.
Regards
G
Hi
I did actually get a service manual for this unit, it is a fairly wicked thick document. I am in South Africa so photo copies may be a nuisance. Maybe scanning and zipping is better. I will see what I can do. The stuff is with a friend though so please give me a little time, a week or so.
The reason I thought the pre amp section on mine is faulty is that it goes through a set up sequence and then flashes the power LED indicating a fault according to the manual. The moment the ribbon from the pre amplifier is disconnected this fault indication dissappears.
All of the output transistors appear fine and I think supply rails 2. Their to regulator stepped supply is a little confusing though. It is very diffycult to fault find this unit as it does not power up to allow me to inject a signal and trace what is happening.
Any advice on typical faults on these units to give closer look would be highly welcome.
Regards
G
I am also currently diaging a cyrus 3. as the thread says.Will be working on it on and off from now on. The service manual zip idea is inviting. please mail me regard payment or instructions.
tubenut
Hi tubenut,
The rail voltages are always there unless a fuse blows. Protection circuits shut down the current sources for the diff. pairs which also kills the bias.
I would check the +/- 15V supplies for the op amps first. Also make sure you don't have a DC offset on the outputs as the unit comes up, that will trip the protection.
Hi tubenut,
The rail voltages are always there unless a fuse blows. Protection circuits shut down the current sources for the diff. pairs which also kills the bias.
I would check the +/- 15V supplies for the op amps first. Also make sure you don't have a DC offset on the outputs as the unit comes up, that will trip the protection.
Hello,
Does anybody know how to undo the modification needed to use the Cyrus 3 with the PSX-R.
I just bought a used Cyrus 3 wich has always been used with a PSX-R. Without the Cyrus is giving a fault, blinking red LED.
Does anybody know how to undo the modification needed to use the Cyrus 3 with the PSX-R.
I just bought a used Cyrus 3 wich has always been used with a PSX-R. Without the Cyrus is giving a fault, blinking red LED.
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