Hi Kind DIY folks- I'm teaching myself a little practical electronics and repair before I jump into full DIY. I'm not an EE but have "STEM" training and an abiding love of music and related stuff. And being of Scottish descent, i hate spending $ unnecessarily.
Back in the early 90s I advised a friend to get a Proton receiver, and it sounded quite nice- essential mid-fi like NAD (or better) with 6dB of headroom lasting tens or hundreds of milliseconds where NAD only usually gives tens and I think ~3dB. So... a little (40wpc) overpowered beastie. I like them. Now that I'm a grown up (arguably at least), I've decided to score one or more of these- lots of clean power, bridgeable, have pre-in and -out. Versatile.
Why am I asking for your time _now_? Because I'm making a stab at repairing a Proton 940 receiver; essentially the D540 amp plus the "receiving" and preamp bits stuck on (particularly nice phono stage and tuner).
I bought it off ebay for ~$50 delivered, and despite having been "tested and working good", it had one dead channel plus obvious capacitor leakage etc. Not worth my effort to return, and any other unit could have similar issues anyhow, considering the age. Looking inside I'm surprised even the one channel worked.
First order of business is re-capping and cleaning all the old electrolyte off the board (and there's a ton!!!).
My first hurdle is pretty significant- apparently the big pair of 10000uf 80wv 85C "vented type" snap-in, 4-terminal caps were custom by nichicon for Proton.
Labeling is white on black including "proton professional" "nichicon" "ce" "85[deg]C" before a diagram of the four terminals with their identification as "(A) (C) blank, (B) 10000uF 80wv" and "NEG BLACK".
The size is ~1" x 2" with four terminals in a kind of offset pattern; the center of each terminal is 1/2" from the exterior of the can, and terminal B(+) is directly across from (-) so a line drawn through them intersects the center of the circle of the can) while A(blank) and C(blank) are offset by ~40 deg such that centers of A and B or B and C are 5mm apart and ~14mm from (-).
Nichicon did respond to a request for information saying these were custom made for Proton and would provide no other information. Suggestions for replacements? There are a few similarly rated caps around but I don't understand the electronics well enough to make an educated substitution. High ripple? low leakage? extra long life? low ESR? "general purpose" "computer grade" "audio grade"?
Second hurdle is better IDing other caps... there are several other caps in that section too, but I can't tell the brand- there is a little triangular icon/logo that looks like an equilateral triangle with arrowheads pasted on top of the vertices. I'm guessing nichicon as well, but they have "CE" like the big ones, and I find no evidence of a "CE" series from them.
Third hurdle is getting the damn electrolyte off the board... its like dried up gel, coffee brown, and seems insoluble in water and 99% isopropanol (well, with effort some will rub off with ISO, but just enough to stain my cleaning rag). And I know non-polar solvents and PCBs/electronics are a bad combo.
I should probably mention that I do have the service manual... and two other D940s, 1 works though totally stock/original equipment (I use it daily, praying nothing goes snap inside) and another sold for parts b/c one channel is dead. I have not examined the latter in any detail- its conceivable the caps in it are fine after all these years but I really doubt it. And have no knowledge of how to test capacitors... and .1F is enough that I'd rather not mess with them if I don't have to...
Any chance I could get a bit more info and suggestions? I have photos but they did not upload as attachments- suggestions for image hosts? Thanks much in advance!!
Back in the early 90s I advised a friend to get a Proton receiver, and it sounded quite nice- essential mid-fi like NAD (or better) with 6dB of headroom lasting tens or hundreds of milliseconds where NAD only usually gives tens and I think ~3dB. So... a little (40wpc) overpowered beastie. I like them. Now that I'm a grown up (arguably at least), I've decided to score one or more of these- lots of clean power, bridgeable, have pre-in and -out. Versatile.
Why am I asking for your time _now_? Because I'm making a stab at repairing a Proton 940 receiver; essentially the D540 amp plus the "receiving" and preamp bits stuck on (particularly nice phono stage and tuner).
I bought it off ebay for ~$50 delivered, and despite having been "tested and working good", it had one dead channel plus obvious capacitor leakage etc. Not worth my effort to return, and any other unit could have similar issues anyhow, considering the age. Looking inside I'm surprised even the one channel worked.
First order of business is re-capping and cleaning all the old electrolyte off the board (and there's a ton!!!).
My first hurdle is pretty significant- apparently the big pair of 10000uf 80wv 85C "vented type" snap-in, 4-terminal caps were custom by nichicon for Proton.
Labeling is white on black including "proton professional" "nichicon" "ce" "85[deg]C" before a diagram of the four terminals with their identification as "(A) (C) blank, (B) 10000uF 80wv" and "NEG BLACK".
The size is ~1" x 2" with four terminals in a kind of offset pattern; the center of each terminal is 1/2" from the exterior of the can, and terminal B(+) is directly across from (-) so a line drawn through them intersects the center of the circle of the can) while A(blank) and C(blank) are offset by ~40 deg such that centers of A and B or B and C are 5mm apart and ~14mm from (-).
Nichicon did respond to a request for information saying these were custom made for Proton and would provide no other information. Suggestions for replacements? There are a few similarly rated caps around but I don't understand the electronics well enough to make an educated substitution. High ripple? low leakage? extra long life? low ESR? "general purpose" "computer grade" "audio grade"?
Second hurdle is better IDing other caps... there are several other caps in that section too, but I can't tell the brand- there is a little triangular icon/logo that looks like an equilateral triangle with arrowheads pasted on top of the vertices. I'm guessing nichicon as well, but they have "CE" like the big ones, and I find no evidence of a "CE" series from them.
Third hurdle is getting the damn electrolyte off the board... its like dried up gel, coffee brown, and seems insoluble in water and 99% isopropanol (well, with effort some will rub off with ISO, but just enough to stain my cleaning rag). And I know non-polar solvents and PCBs/electronics are a bad combo.
I should probably mention that I do have the service manual... and two other D940s, 1 works though totally stock/original equipment (I use it daily, praying nothing goes snap inside) and another sold for parts b/c one channel is dead. I have not examined the latter in any detail- its conceivable the caps in it are fine after all these years but I really doubt it. And have no knowledge of how to test capacitors... and .1F is enough that I'd rather not mess with them if I don't have to...
Any chance I could get a bit more info and suggestions? I have photos but they did not upload as attachments- suggestions for image hosts? Thanks much in advance!!
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Capacitor replacements questions and a bit more
Hi folks- I need help finding a useful substitute for some 10000uF 80wv 85degC 4 terminal snap-in capacitors that were custom built by Nichicon for Proton. I've put a longer description, etc. here:
Proton D940 receiver repair assistance for noob
any assistance with any of these issues would be appreciated.
Hi folks- I need help finding a useful substitute for some 10000uF 80wv 85degC 4 terminal snap-in capacitors that were custom built by Nichicon for Proton. I've put a longer description, etc. here:
Proton D940 receiver repair assistance for noob
any assistance with any of these issues would be appreciated.
How about a small adapter board that the new standard format caps mount on,
with board to board terminals to fit the main board. They do it with op amps,
why not electrolytics?
Here's a similar adapter board project.
Tektronix 494AP Spectrum Analyzer Repair - Page 1
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It’s just glue, not electrolyte.
Panasonic TUP caps have a common 4-pin pattern.
Click ‘Go Advanced’ then Manage Attachments to permanently attach photos.
How to attach images to your posts.
Panasonic TUP caps have a common 4-pin pattern.
Click ‘Go Advanced’ then Manage Attachments to permanently attach photos.
How to attach images to your posts.
Thread merged.
before dismounting, check the switches and relays, the protons are full of false contact.
then, determine if the preamp or amp is in "default" by removing the jumpers that connect "pre out and main in".
but first, deoxit or any other contact cleaner on all contactors and rotary contactors.
then, determine if the preamp or amp is in "default" by removing the jumpers that connect "pre out and main in".
but first, deoxit or any other contact cleaner on all contactors and rotary contactors.
Thanks folks, and apologies for the double post- i was trying to access a few more eyeballs and brains.
So- pictures.... I missed the size limits. So these have been carefully (well, not too carefully) edited and compressed. I think everything important is still visible.
I'll do the whole deoxide-it thing, see if theres still juice going to the preamp (having ripped these caps out I'm not certain there is- I'd wager not but haven't traced circuits to see if I killed its power) and test that by feeding its signal to another amp.
Having pulled these, I'm not going to put them back in right now but I will follow the troubleshooting suggested with the unexamined, dead-channel unit.
I expected the brown gunk to be electrolyte both b/c of age and location ... and neither the fully-functional D940 not the dead-channel "parts" unit has any of this brown stuff visible.
WRT replacements for the big caps, perhaps these are drop-in replacements:
CEAWF1K103M42 MARCON capacitor 10,000uF 80V Aluminum Electrolytic Snap In 2020030725
Apparently the manufacturer (Marcon brand caps) is also owned by the owner of Nichicon. Size and lead/connector description (A and C "null") and arrangement of the 4 leads looks good, but these guys have different tolerances than the original; the service manual describes it as +50/-10% tolerance. These guy are $10, so relatively attractive price-wise. I have no idea if any of these (besides physical dimensions, uF and V ratings) are terribly relevant.
Its clear from the trace that the two extra leads don't do anything- on one side ("B+") all 3 non-negative leads are soldered in the same trace, and the other ("B-") the "A" and "C" leads are soldered to traces that are not part of any circuit... clearly just structural reinforcement on the B- side. Dunno about the B+ side.
If all of the last paragraph is correct, I can use any lead arrangement so long as the cap gets physically secured... like a clamp or glue.
THANKS AGAIN (yes, I'm shouting b/c I really mean it 😀 )
So- pictures.... I missed the size limits. So these have been carefully (well, not too carefully) edited and compressed. I think everything important is still visible.
I'll do the whole deoxide-it thing, see if theres still juice going to the preamp (having ripped these caps out I'm not certain there is- I'd wager not but haven't traced circuits to see if I killed its power) and test that by feeding its signal to another amp.
Having pulled these, I'm not going to put them back in right now but I will follow the troubleshooting suggested with the unexamined, dead-channel unit.
I expected the brown gunk to be electrolyte both b/c of age and location ... and neither the fully-functional D940 not the dead-channel "parts" unit has any of this brown stuff visible.
WRT replacements for the big caps, perhaps these are drop-in replacements:
CEAWF1K103M42 MARCON capacitor 10,000uF 80V Aluminum Electrolytic Snap In 2020030725
Apparently the manufacturer (Marcon brand caps) is also owned by the owner of Nichicon. Size and lead/connector description (A and C "null") and arrangement of the 4 leads looks good, but these guys have different tolerances than the original; the service manual describes it as +50/-10% tolerance. These guy are $10, so relatively attractive price-wise. I have no idea if any of these (besides physical dimensions, uF and V ratings) are terribly relevant.
Its clear from the trace that the two extra leads don't do anything- on one side ("B+") all 3 non-negative leads are soldered in the same trace, and the other ("B-") the "A" and "C" leads are soldered to traces that are not part of any circuit... clearly just structural reinforcement on the B- side. Dunno about the B+ side.
If all of the last paragraph is correct, I can use any lead arrangement so long as the cap gets physically secured... like a clamp or glue.
THANKS AGAIN (yes, I'm shouting b/c I really mean it 😀 )
Attachments
I think my post should have been called something like "choosing capacitors"... b/c thats what I'm doing.
Nope, it's become a recap thread - the most common, so you're on common ground there, checking sources, making lists and replacing parts - fun!
The 2 caps may have 4 pins but the sleeve label states 10,000uF, 80Volts, so there are 2 spare pins for physical security - backed up by glue as well. Check with a multimeter if any pins or the copper tracks they connect to, don't seem to connect to others. This should be backed up by looking at the PCB to check which pins are "do nothing" by connecting to nothing or a few connect to ground. Verify on Marcon's datasheet what pins are what before buying (they are not known to be good quality either, BTW)
The 2 caps may have 4 pins but the sleeve label states 10,000uF, 80Volts, so there are 2 spare pins for physical security - backed up by glue as well. Check with a multimeter if any pins or the copper tracks they connect to, don't seem to connect to others. This should be backed up by looking at the PCB to check which pins are "do nothing" by connecting to nothing or a few connect to ground. Verify on Marcon's datasheet what pins are what before buying (they are not known to be good quality either, BTW)
I understand (and the PCB shows) the A and C tabs have purelu mechanical, not electrical, function. So anything I can shove in there and manage to shove in there with proper polarity and good, short electrical paths - pref. the original hole thru the PCB.
Based on this I've found another couple possible replacements but I'd like to intellegently chose a device.
So just to make sure I know what I'm asking and looking for... I believe I need caps that meet or exceed the originals' rated C,T and V with relatively high ripple current and low ESR or where listed low tan[delta].
What is adequately high ripple? 3A? 6A?
And I don't think these are filter caps, but storage... so ripple matters... how?
"Low enough" ESR? 0.01 ohm, .1 ohm, 1 ohm? [I know they aren't exactly the same, but "low" reactance... or high Q]
tan[delta] 0.1, 0.5? 1? 2? My guess here is just "lower is better" if I have a choice.
Same with leakage.
And should I stay away from caps intended for e.g., computer use or motors? Provided they fit the requirements of course.
Based on this I've found another couple possible replacements but I'd like to intellegently chose a device.
So just to make sure I know what I'm asking and looking for... I believe I need caps that meet or exceed the originals' rated C,T and V with relatively high ripple current and low ESR or where listed low tan[delta].
What is adequately high ripple? 3A? 6A?
And I don't think these are filter caps, but storage... so ripple matters... how?
"Low enough" ESR? 0.01 ohm, .1 ohm, 1 ohm? [I know they aren't exactly the same, but "low" reactance... or high Q]
tan[delta] 0.1, 0.5? 1? 2? My guess here is just "lower is better" if I have a choice.
Same with leakage.
And should I stay away from caps intended for e.g., computer use or motors? Provided they fit the requirements of course.
ps- the Marcon are what seem to be the closest physically- tabs all in the same places, good C, V, T. They are also one of the cheapest, ~ $10/ea.
There seem to be some CDE caps meeting the C,V and T yet have 18,000 hours expected life rather than the 1000-2000 of most others.
I never see endurance even discussed WRT "audio" electrolytic caps.
There seem to be some CDE caps meeting the C,V and T yet have 18,000 hours expected life rather than the 1000-2000 of most others.
I never see endurance even discussed WRT "audio" electrolytic caps.
Capacitor life tests are typically rated at maximum ripple current and temperature and so even a 2000 Hr cap would last many 1000's of hours as the ratings were derated.
For example a 12 volt bulb across 12 volts might have a 1000 Hr life. Drop the voltage to 11V and it could be 2000 Hr. Drop it to 10V and it might be 5000Hr. Drop it to 8V and it could last 20,000 Hr. Its not a linear thing.
Don't be afraid of drilling the board to neatly accommodate replacement Snap In types.
You won't come close to maximum ratings in an audio amp.
For example a 12 volt bulb across 12 volts might have a 1000 Hr life. Drop the voltage to 11V and it could be 2000 Hr. Drop it to 10V and it might be 5000Hr. Drop it to 8V and it could last 20,000 Hr. Its not a linear thing.
Don't be afraid of drilling the board to neatly accommodate replacement Snap In types.
You won't come close to maximum ratings in an audio amp.
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