CR-2040 Project
- Thread starter zaskarx
- Start date
zaskarx
Active Member
Spent the weekend removing the main filter caps...what a bear of a project! The caps are heavily glued to the circuit board, which itself is relatively unsupported and flimsy. The caps are also glued to the support bracket and each other. The screws that hold the support bracket are also making them impossible to remove without stripping the screws. Yamaha really did not want these suckers to come out!
After about 5 hours of de-soldering, drilling, grinding with a Dremel, snipping, and wiggling, the caps are finally out. Unfortunately, despite my best efforts, a few spots on the foil soldering pads have lifted, I should still have plenty to solder to, but I absolutely hate when that happens
. Now to clean up the glue residue which seems to be starting to corrode a few components...
After about 5 hours of de-soldering, drilling, grinding with a Dremel, snipping, and wiggling, the caps are finally out. Unfortunately, despite my best efforts, a few spots on the foil soldering pads have lifted, I should still have plenty to solder to, but I absolutely hate when that happens
. Now to clean up the glue residue which seems to be starting to corrode a few components...Attachments
zaskarx
Active Member
Got the speaker terminal brackets back from the 3D printer, turned out pretty good! Found a good deal on high quality binding posts from Zu audio. If I had to do it over again I might have gone with a slightly smaller diameter post, but these are really nice and will work just fine.
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Really careful..
zaskarx
Active Member
Hmm...maybe my imagination isn't very good but what would be a worse case scenario? Receiver is bumped while powered on causing a speaker cable to be knocked loose and short the positive and negative terminals? If there is something I'm not thinking of let me know - I definitely don't want to risk damage and am willing to buy better insulated binding posts if it makes sense...
Exactly. Give the man a Ceee gar.
zaskarx
Active Member
Finally making some progress...
MM daughter board - replaced e-caps, would there be any benefit in bypassing the output caps C525 and C526 with film caps or is that venturing into the realm of audiophoolery? Any other tweaks that would benefit the phono stage? I plan to listen to a lot of vinyl with this receiver.
Tone control/preamp - replaced e-caps, all values 4.7uf and under with Wima films, the rest with a mixture of Nichicon and Elna audio grade e-caps. Also, I added sockets for the preamp 4558 opamps, are there any benefits to be had in updating these to more modern opamps? I can't imagine these Carter era opamps are doing the sound any favors; then again they don't seem to be in the signal path so hard to know for sure.
Main driver boards - replaced e-caps, cleaned and re-greased all transistors, installed nice new Bourns trimpots and matched the values to the old pots.
MM daughter board - replaced e-caps, would there be any benefit in bypassing the output caps C525 and C526 with film caps or is that venturing into the realm of audiophoolery? Any other tweaks that would benefit the phono stage? I plan to listen to a lot of vinyl with this receiver.
Tone control/preamp - replaced e-caps, all values 4.7uf and under with Wima films, the rest with a mixture of Nichicon and Elna audio grade e-caps. Also, I added sockets for the preamp 4558 opamps, are there any benefits to be had in updating these to more modern opamps? I can't imagine these Carter era opamps are doing the sound any favors; then again they don't seem to be in the signal path so hard to know for sure.
Main driver boards - replaced e-caps, cleaned and re-greased all transistors, installed nice new Bourns trimpots and matched the values to the old pots.
zaskarx
Active Member
Made a bit more progress, mounted the speaker terminals to the 3D printed brackets. I was tempted to replace the internal wiring to the speaker terminals given that the stock cable is a rather flimsy, low-gauge ribbon cable, but that would mean disturbing wire wraps which I am am extremely loathe to do. Luckily, I was able to desolder the cable ends from the spring clip circuit board and solder them through the holes in the new speaker terminals with little difficulty - there was just enough slack in the ribbon cable to do so. The old spring clip board can technically be remounted given the ribbon cables weren't altered in any way.
One snag I ran into, the new relay, Panasonic HC4-HP-DC12V, had pins that were slightly too wide for the existing circuit board holes. Not wanting to drill into the board, I disassembled the old relay, which wasn't too worn, and cleaned the contacts. Looks like Digikey has MY4-02-DC12 back in stock, I may order one; haven't decided yet.
On the MM phono board, I decided to replace output capacitors with C525 and C526 with Wima film caps, 10uf 50v. They are pretty big but there is plenty of room on that board.
Now working on soldering in new lamps...
One snag I ran into, the new relay, Panasonic HC4-HP-DC12V, had pins that were slightly too wide for the existing circuit board holes. Not wanting to drill into the board, I disassembled the old relay, which wasn't too worn, and cleaned the contacts. Looks like Digikey has MY4-02-DC12 back in stock, I may order one; haven't decided yet.
On the MM phono board, I decided to replace output capacitors with C525 and C526 with Wima film caps, 10uf 50v. They are pretty big but there is plenty of room on that board.
Now working on soldering in new lamps...
HC4 is identicle to the MY4. These are both drop in replacements for the DEC TYPE MS4U 24VDC after you snip off the NC row of unused pins. At least they fit for me without drilling.
They are a snug fit.
NC - normally closed
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zaskarx
Active Member
Inching towards the finish line...the cabinet is almost ready, needs another coat of polyurethane. I'm really pleased with how it has turned out so far, the wood is faithful to the original while having a higher quality look and feel to it.
I'm struggling a bit with the bias pots. The new Bourns single turn pots are extremely touchy and the bias is somewhat jumpy on both channels, breathe on them and they will move 50mv. Is there another option that might be better? Are there any funky diodes in the PS that I missed that could be causing jumpiness? This is the style I am using: https://www.mouser.com/ProductDetail/Bourns/3329S-1-102LF?qs=sGAEpiMZZMvygUB3GLcD7swPUEOakrxn23fTQNlNSR4=.
I'm struggling a bit with the bias pots. The new Bourns single turn pots are extremely touchy and the bias is somewhat jumpy on both channels, breathe on them and they will move 50mv. Is there another option that might be better? Are there any funky diodes in the PS that I missed that could be causing jumpiness? This is the style I am using: https://www.mouser.com/ProductDetail/Bourns/3329S-1-102LF?qs=sGAEpiMZZMvygUB3GLcD7swPUEOakrxn23fTQNlNSR4=.
zaskarx
Active Member
HC4 is identicle to the MY4. These are both drop in replacements for the DEC TYPE MS4U 24VDC after you snip off the NC row of unused pins. At least they fit for me without drilling.
They are a snug fit.
NC - normally closed
I did snip off the unused pins, which are more like tabs as compared to the pins on the original. Maybe I wasn't forceful enough in trying to seat it?
Nice work! Please keep us posted on your progress.
I recently got a 2040, but don't have much time to upgrade the speaker binding posts right now. What's the best way to connect some 10 AWG speaker wires to it? Will something likes this work?
https://www.amazon.com/Nakamichi-Sp...s&qid=1556233715&s=gateway&sr=8-2-spons&psc=1
I recently got a 2040, but don't have much time to upgrade the speaker binding posts right now. What's the best way to connect some 10 AWG speaker wires to it? Will something likes this work?
https://www.amazon.com/Nakamichi-Sp...s&qid=1556233715&s=gateway&sr=8-2-spons&psc=1
jbailey930
AK Member
Also curious about using bi-wires for Vandy’s with a 2040. Splice them for a single connection?
zaskarx
Active Member
Hmm...10 gauge is pretty big, it may be too big for those connectors. You could buy a cheap roll of 16 gauge wire from Amazon and use that temporarily, it'll definitely fit the stock spring clips and should work as well as 10 gauge unless you have an insanely long run.
Do you mean on the amp side? If so you could use both A and B speaker terminals and change the switch to A + B on the front panel.
zaskarx
Active Member
Ok, CR-2040 is finally finished! I ended up replacing the finicky pots with 20 turn units and all is well. Replaced lamps with new ones from DJWOJO and they look great. The tuner dial pointer is slightly off on FM and I don't have the tools or knowledge to properly align it, nor does anyone else in a city of 5 million as it turns out. I've been beating the bushes to find someone but no luck sadly, tuner alignment is truly a dead art.
Overall the receiver sounds excellent, but hard to tell if it sounds any better than my CR-2020. The veneered case turned out good too, but not perfect. All in all it was a successful project but I guess I'm just a bit underwhelmed and am going to sell this one. Might end up sticking to projects that do not have a wood case or a tuner in the future!
Anyways, now that I've been through it hopefully I can help out anyone else who has a CR-2040, it is still one of Yamaha's best looking receivers in my opinion.
Overall the receiver sounds excellent, but hard to tell if it sounds any better than my CR-2020. The veneered case turned out good too, but not perfect. All in all it was a successful project but I guess I'm just a bit underwhelmed and am going to sell this one. Might end up sticking to projects that do not have a wood case or a tuner in the future!
Anyways, now that I've been through it hopefully I can help out anyone else who has a CR-2040, it is still one of Yamaha's best looking receivers in my opinion.
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