Hi, new member with a question here.
I have an Arcam AVR300 with the not-so-uncommon DAC problem (either won't accept digital input, or puts out lots of speaker wrecking static when you try), and am unfortunately out of warranty.
Arcams solution is to replace the digital board or to replace the zener(?) diodes I believe. If they can replace the diodes, then I don't see why I can't do it myself?
Can anyone give me a few pointers such as:
1) How to test the diodes?
2) How to know what replacements to get
3) Are they heat sensitive, ie should I isolate them when soldering in new ones?
I don't suppose there is anyone out there who has done this themselves, but if there is I'd be very greatful for your advice.
Thanks,
Phil
PS - lots more info on the problem on www.avforums.com/forums/archive/index.php/t-239068.html
I have an Arcam AVR300 with the not-so-uncommon DAC problem (either won't accept digital input, or puts out lots of speaker wrecking static when you try), and am unfortunately out of warranty.
Arcams solution is to replace the digital board or to replace the zener(?) diodes I believe. If they can replace the diodes, then I don't see why I can't do it myself?
Can anyone give me a few pointers such as:
1) How to test the diodes?
2) How to know what replacements to get
3) Are they heat sensitive, ie should I isolate them when soldering in new ones?
I don't suppose there is anyone out there who has done this themselves, but if there is I'd be very greatful for your advice.
Thanks,
Phil
PS - lots more info on the problem on www.avforums.com/forums/archive/index.php/t-239068.html
Diode Replacement/ Cap replacement
My Arcam 300 (AVR300) has a darkened spot on the d.A. board
right underneath the 3300uf Cap.
Also, the cap has a bulging top!
Id like to obtain the PDF file with the diodes
that need upgrading. I'll be pulling this
board to replace that cap, and want to upgrade
the correct diodes at the same time, or replace the board!
The browning of the board is unnerving
My Arcam 300 (AVR300) has a darkened spot on the d.A. board
right underneath the 3300uf Cap.
Also, the cap has a bulging top!
Id like to obtain the PDF file with the diodes
that need upgrading. I'll be pulling this
board to replace that cap, and want to upgrade
the correct diodes at the same time, or replace the board!
The browning of the board is unnerving
Okay i had the same problem with mine so i replaced the diodes following arcams guide and the digital input was repaired. But now the amp sounds rubbish, there is just to much bass and very little midrange and it sounds a bit harsh. Could this be something to do with the diodes i used?
FAIRCHILD SEMICONDUCTOR
BRIDGE RECTIFIER, 1.5A, 200V, DO204
Diode Type:Standard Recovery; Repetitive Reverse Voltage Vrrm Max:200V; Forward Current If(AV):1.5A; Forward Voltage VF Max:1.4V; Forward Surge Current Ifsm Max:50A; Operating Tempera;
If some one could help that would be great.
FAIRCHILD SEMICONDUCTOR
BRIDGE RECTIFIER, 1.5A, 200V, DO204
Diode Type:Standard Recovery; Repetitive Reverse Voltage Vrrm Max:200V; Forward Current If(AV):1.5A; Forward Voltage VF Max:1.4V; Forward Surge Current Ifsm Max:50A; Operating Tempera;
If some one could help that would be great.
Normal diodes in a PSU should have zero impact on the sound quality (as you describe).
These should be a suitable replacement for the IN5393
ON SEMICONDUCTOR|MR856RL|DIODE, FAST RECOVERY, 3A 600V | CPC
http://www.datasheetcatalog.org/datasheet2/6/0ed3rxt81348wu00x97ti2q1u2py.pdf
Very often when doing mods or changing components personal expectation gets in the way and you convince yourself its not as good etc when in reality nothing has changed.
Just swapping rectifiers will not alter the basic sound at all...
These should be a suitable replacement for the IN5393
ON SEMICONDUCTOR|MR856RL|DIODE, FAST RECOVERY, 3A 600V | CPC
http://www.datasheetcatalog.org/datasheet2/6/0ed3rxt81348wu00x97ti2q1u2py.pdf
Very often when doing mods or changing components personal expectation gets in the way and you convince yourself its not as good etc when in reality nothing has changed.
Just swapping rectifiers will not alter the basic sound at all...
We have a 300 that shuts off during The initialization; it would go to Volume, then double clicks and then to off power.
Replacing a bulging cap on the main board did not change the shutting off.
The cap was the monster 3300uF 25V.
it is still shutting down during the test sequence at start up.
It gets to Volume, then shuts down.
Replacing a bulging cap on the main board did not change the shutting off.
The cap was the monster 3300uF 25V.
it is still shutting down during the test sequence at start up.
It gets to Volume, then shuts down.
I'm just about to try to repair mine tomorrow. I have found a few links, including this one https://www.avforums.com/threads/arcam-repair-third-party-for-avr-300.1780356/ which had some pictures of another unit that had failed but been successfully repaired.
Mine has not actually got to that stage, but here are some photos.
In the shot of the reverse of the board you can see that the legs of the diodes have cracked away from the solder around them.
One slightly annoying thing is that the capacitor which was on top of these diodes is a 25V 3300uF device, but on the circuit diagram it is supposed to be a 16V one. I stupidly ordered the parts off the circuit diagram and didn't check if they were what was actually in the board. All the others seems to match the diagram.
I wonder if they changed this up after having had some problem?
I've got 400V 3A 1N5404 diodes to replace the failed ones (1N4004 400V 1A), and they are five times the size (DO-201AD 9.5 mm long x 5.3 mm size vs DO-204AL 5 mm long x 2.7 mm size) so they should all stand up off the board, which I gather was the original solution applied when these were serviced under warranty https://forum.audiogon.com/discussions/avr-300-powers-up-8-seconds-powers-off.
Condor Audio have posted a guide to their work restoring these amps, which is at http://www.condoraudio.com/wp-content/uploads/Projects/Arcam-AVR350-AV-Receiver-Audiophile-Upgrade-Repair.pdf and you can see on the page 'Main PSU Motherboard' they have done the same for all the diodes.
Anyway, fingers crossed, if it works I'll be very happy!
Mine has not actually got to that stage, but here are some photos.
In the shot of the reverse of the board you can see that the legs of the diodes have cracked away from the solder around them.
One slightly annoying thing is that the capacitor which was on top of these diodes is a 25V 3300uF device, but on the circuit diagram it is supposed to be a 16V one. I stupidly ordered the parts off the circuit diagram and didn't check if they were what was actually in the board. All the others seems to match the diagram.
I wonder if they changed this up after having had some problem?
I've got 400V 3A 1N5404 diodes to replace the failed ones (1N4004 400V 1A), and they are five times the size (DO-201AD 9.5 mm long x 5.3 mm size vs DO-204AL 5 mm long x 2.7 mm size) so they should all stand up off the board, which I gather was the original solution applied when these were serviced under warranty https://forum.audiogon.com/discussions/avr-300-powers-up-8-seconds-powers-off.
Condor Audio have posted a guide to their work restoring these amps, which is at http://www.condoraudio.com/wp-content/uploads/Projects/Arcam-AVR350-AV-Receiver-Audiophile-Upgrade-Repair.pdf and you can see on the page 'Main PSU Motherboard' they have done the same for all the diodes.
Anyway, fingers crossed, if it works I'll be very happy!
It worked! I'm quite relieved as I was not very happy with how the soldering was looking. The copper pad where the overheating was worst just came right off so I just joined the legs of the two diodes that met there. Another thing I found was that the 3 A diodes had legs that were thicker than the holes in the motherboard, so after taking the old diodes off I had to drill the holes out to make them all wider.
The 16 V 3300 uF cap is looking quite small compared to the one it replaced, but given the time of year I thought I'd rather try it and see if it worked instead of ordering a 25 V part. and waiting till the New Year with no music. It is rectifying an 8 V ac signal so 16 V should do. If this was upgraded due to these caps failing prematurely, it was probably the temperature not the voltage that was to blame.
Anyway, I'm very happy to be able to keep this amp going, it does all I need and what is more, my wife loves it too.
The 16 V 3300 uF cap is looking quite small compared to the one it replaced, but given the time of year I thought I'd rather try it and see if it worked instead of ordering a 25 V part. and waiting till the New Year with no music. It is rectifying an 8 V ac signal so 16 V should do. If this was upgraded due to these caps failing prematurely, it was probably the temperature not the voltage that was to blame.
Anyway, I'm very happy to be able to keep this amp going, it does all I need and what is more, my wife loves it too.
To be fair, this amp was built in 2004, in China. They brought the manufacture back to England from China in 2010, when the AVR 600 was the current model. This sort of problem seems to be from the era when the boards were assembled in China, and I'd hope it might not reflect their current line up.
Unbelievable...let's blame China.
Nothing to do with a lousy design that surely originated at Arcam of England? Those zeners, the worst voltage regulation solution used to save on cost, are under-rated for the job. The heat dissipation caused all solder joints around that area to crack and loose conductivity - I see 10 of 'em.
I do take your point and I don't mean to blame the assemblers and excuse the designers, I just didn't want anyone to think was an amp in production now, and to point out that Arcam did make changes after these issues became apparent.
Pardon me for resurrecting an ancient thread, but I've been asked by a friend to have a stab at resurrecting his ancient AVR300.
His has the same symptoms as those mentioned above: it won't start up, some clicking relays and after a few seconds a flashing red LED.
I've (probably) traced the problem to the main PCB, where the same diodes (those around C121, the 25V/3300uF capacitor and U105/U106, the +/-12V regulators) have caused a black mark on the PCB.
Is it safe to not only swap all 1n4004 diodes for 3A types, but to also upgrade all the positive and negative Voltage regulator IC's for 1,5 -2 2A types? I can't find suitable types for all of them... Are the current heatsinks sufficient to for 2A voltage regulators? I would think so, but I'm not sure. Thought I'd check...
Thanks in advance for any and all help.
His has the same symptoms as those mentioned above: it won't start up, some clicking relays and after a few seconds a flashing red LED.
I've (probably) traced the problem to the main PCB, where the same diodes (those around C121, the 25V/3300uF capacitor and U105/U106, the +/-12V regulators) have caused a black mark on the PCB.
Is it safe to not only swap all 1n4004 diodes for 3A types, but to also upgrade all the positive and negative Voltage regulator IC's for 1,5 -2 2A types? I can't find suitable types for all of them... Are the current heatsinks sufficient to for 2A voltage regulators? I would think so, but I'm not sure. Thought I'd check...
Thanks in advance for any and all help.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.