Re-Capping SX-780?

Nolannniah

Active Member
I currently have some high voltage issues, which I am working through with some other members.

I've read some other posts about recapping their units, and was wondering if it would be advisable. I know the original owner of my 780 had work done to it 25+ years ago. A lot of the caps look different and newer than what they should be (basing on other post and pictures from the before pics). With this being said, all of the ones in question are rated at 85C vs. 105C, which seems to be the standard here at AK. Should this be a concern? Do caps go bad from non use?
I have had it 25 some odd years, and it has set in a closet for a good while. I have used it from time to time, but it has not been put into regular use (which is what I plan on doing after repairs are done). I found these issues I'm having now after I pulled it out of storage.

I plan on repairing the high voltage issue first, but from what I read about ESR values and ripple current (see below); could the caps cause some voltage issues and trip my relay?

"Aluminum and tantalum electrolytic capacitors with non solid electrolyte have much higher ESR values, up to several ohms, and ESR tends to increase with frequency due to effects of the electrolyte. A very serious problem, particularly with aluminum electrolytics, is that ESR increases over time with use; ESR can increase enough to cause circuit malfunction and even component damage, [1] although measured capacitance may remain within tolerance. While this happens with normal aging, high temperatures and large ripple current exacerbate the problem. In a circuit with significant ripple current, an increase in ESR will increase heat dissipation, thus accelerating aging.

Electrolytic capacitors rated for high-temperature operation and of higher quality than basic consumer-grade parts are less susceptible to become prematurely unusable due to ESR increase. A cheap electrolytic capacitor may be rated for a life of less than 1000 hours at 85°C (a year is about 9000 hours). Higher-grade parts are typically rated at a few thousand hours at maximum rated temperature, as can be seen from manufacturers' datasheets. Electrolytics of higher capacitance have lower ESR; if ESR is critical, specification of a part of larger capacitance than is otherwise required may be advantageous."

So, if you have some input and experience in my re-cap dilemma, please let me know-:scratch2:
Thanks
 
Use Nichicon UPW or UHE for the cea caps, or the Panasonic (I forgot, can't find them) and the cssa csza and ceanl caps get Nichicon UKL caps.

0.1uf to 1.0uf get stacked film caps

the lists HAVE the good caps in them. look at this: List of lists, SX-780 list

ESR comments came from WHERE???

ESR is of more concern in switching power supplies, not audio equipment.
 
Panasonic FC or FM series.

Yes electrolytics degrade over time from non use also. The electrolytic (which is a liquid paste) eventually dries out because the seal on the bottom degrades over time. As they dry out, you lose sound quality. And they eventually short. But we try to get to them before they short.

Go with the one's Mark recommends. They are a good match for the locations outlined.
 
Thanks guys!

MTF: The ESR stuff came from a general read somewhere (didn't save the page), but makes sense now...couldn't find anything in that read related to audio.
 
Mark,

The links you gave have old cap lists that aren't complete and don't contain the cap types you specified. Please check my work below (hope this doesn't actually exist somewhere). Notes to the right show what I changed. I also included the relay and the 3 voltage regulators that get wicked hot (along with mica insulator kits). LED lights and the heatsink mod should finish the job.

Tuner Assy
C27 2.2 50V cea 2.2/50V 647-UPW1H2R2MDD
C28 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C34 1 50V cea 1/50V 667-ECQ-V1H105JL film
C35 22 16V cea 22/16V 647-UPW1C220MDD
C37 6.8 6V csza 6/50V 647-UKL1H6R8KDDANA UKL
C38 1 50V ceanl 1/50V 667-ECQ-V1H105JL film
C40 1 50V ceanl 1/50V 667-ECQ-V1H105JL film
C41 1 50V cea 1/50V 667-ECQ-V1H105JL film
C44 220 16V cea 220/16V 647-UPW1C221MPD
C53 220 16V cea 220/16V 647-UPW1C221MPD
C60 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C61 3.3 50V cea 3.3/50V 647-UPW1H3R3MDD
C67 22 16V cea 22/16V 647-UPW1C220MDD
C71 10 16V cea 10/16V 647-UPW1C100MDD

Amp Assy
C103 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C104 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C105 470 6V cea 470/6.3 647-UPW0J471MPD
C106 470 6V cea 470/6.3 647-UPW0J471MPD
C117 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C118 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C201 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C202 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C205 0.022 50V cqma 667-ECQ-V1H223JL3 film
C206 0.022 50V cqma 667-ECQ-V1H223JL3 film
C207 1 50V ceanl 1/50V 667-ECQ-V1H105JL film
C208 1 50V ceanl 1/50V 667-ECQ-V1H105JL film
C213 47 6V cea 470/6.3V 647-UPW0J470MDD6
C214 47 6V cea 470/6.3V 647-UPW0J470MDD6
C217 4.7 25V cea 4.7/25V 647-UPW1E4R7MDD
C218 4.7 25V cea 4.7/25V 647-UPW1E4R7MDD
C227 0.22 50V cea 0.22/50V 667-ECQ-V1H224JL film
C228 0.22 50V cea 0.22/50V 667-ECQ-V1H224JL film
C229 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C230 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C301 100 25V cea 100/25V 647-UPW1E101MED
C302 100 25V cea 100/25V 647-UPW1E101MED
C303 100 25V cea 100/25V 647-UPW1E101MED
C304 100 25V cea 100/25V 647-UPW1E101MED
C305 47 35V cea 47/35V 647-UPW1V470MED
C306 47 35V cea 47/35V 647-UPW1V470MED
C307 100 50V cea 100/50V 647-UPW1H101MPD
C308 100 50V cea 100/50V 647-UPW1H101MPD
C309 2.2 50V cea 2.2/50V 647-UPW1H2R2MDD
C310 2.2 50V cea 2.2/50V 647-UPW1H2R2MDD
C311 220 16V cea 220/16V 647-UPW1C221MPD svs manual says 100uF but 220uF is correct
C314 470 63V cea 470/63V 647-UPW1J471MHD6
C315 220 63V cea 220/63V 647-UPW1J221MPD6
C316 47 50V cea 47/50V 647-UPW1H470MED
C317 33 16V cea 33/16V 647-UPW1C330MDD
C318 10 16V cea 10/16V 647-UPW1C100MDD
C319 47 16V cea 47/16V 647-UPW1C470MDD
C324 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C325 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C326 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C327 4.7 35V cea 4.7/50V 647-UPW1H4R7MDD
C401 0.47 50V cea 0.47/50V 647-UPW1HR47MDD
C402 0.47 50V cea 0.47/50V 647-UPW1HR47MDD
C403 0.47 50V cea 0.47/50V 647-UPW1HR47MDD
C404 0.47 50V cea 0.47/50V 647-UPW1HR47MDD
C405 10 16V cea 10/16V 647-UPW1C100MDD
C406 220 6V cea 220/6.3V 647-UPW0J221MED
4.7 35V 4.7/50V 647-UPW1H4R7MDD not in svs manual
Q19 512-KSC2073TU
Q20 512-KSA940TU
Q25 512-KSC2073TU
relay 653-MY4-02-DC48
mica 532-4880M 3 needed

enlarge heatsink on Q20
LED bulbs (3 needed - check fleabay)
 
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I found all Caps except the cssa & csza part number ones. Only csza part number one I could find was C37, coming from PA1001-A. Am I missing something here?
 
Not sure the question? Somewhat risky using this list until Mark approves, so I'd wait till he has a chance to look at it. I'm getting ready to restore my SX780 also. After creating a Mouser account, select "part list importer" from the "services and tools" drop down. Then you paste the following list and select "import". All parts are in stock. Cost is $30.67
647-UPW1H2R2MDD
647-UPW1H4R7MDD
667-ECQ-V1H105JL
647-UPW1C220MDD
647-UKL1H6R8KDDANA
667-ECQ-V1H105JL
667-ECQ-V1H105JL
667-ECQ-V1H105JL
647-UPW1C221MPD
647-UPW1C221MPD
647-UPW1H4R7MDD
647-UPW1H3R3MDD
647-UPW1C220MDD
647-UPW1C100MDD
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UPW0J471MPD
647-UPW0J471MPD
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UPW1H4R7MDD
647-UPW1H4R7MDD
667-ECQ-V1H223JL3
667-ECQ-V1H223JL3
667-ECQ-V1H105JL
667-ECQ-V1H105JL
647-UPW0J470MDD6
647-UPW0J470MDD6
647-UPW1E4R7MDD
647-UPW1E4R7MDD
667-ECQ-V1H224JL
667-ECQ-V1H224JL
647-UKL1H2R2KDDANA
647-UKL1H2R2KDDANA
647-UPW1E101MED
647-UPW1E101MED
647-UPW1E101MED
647-UPW1E101MED
647-UPW1V470MED
647-UPW1V470MED
647-UPW1H101MPD
647-UPW1H101MPD
647-UPW1H2R2MDD
647-UPW1H2R2MDD
647-UPW1C221MPD
647-UPW1J471MHD6
647-UPW1J221MPD6
647-UPW1H470MED
647-UPW1C330MDD
647-UPW1C100MDD
647-UPW1C470MDD
647-UPW1H4R7MDD
647-UPW1H4R7MDD
647-UPW1H4R7MDD
647-UPW1H4R7MDD
647-UPW1HR47MDD
647-UPW1HR47MDD
647-UPW1HR47MDD
647-UPW1HR47MDD
647-UPW1C100MDD
647-UPW0J221MED
647-UPW1H4R7MDD
512-KSC2073TU
512-KSA940TU
512-KSC2073TU
653-MY4-02-DC48
532-4880M
 
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From MTF's list via part number reference via type of cap to use (part number ref.), your fist list is dead on. I've scrubbed the lists a couple of times, and have found no error...MTF?

Note: the SX-780 does not have a cssa cap, that I could find.
 
C205 and C206 are ceramic, so I wasn't sure if they needed replacing, but I figured films wouldn't hurt. There was some discussion in the thread referenced in the list of lists.

http://www.audiokarma.org/forums/showthread.php?t=213265&highlight=Recap+list

C401-404 are between .1 and 1uF, so would be candidates for films, but they are only part of the tuning signal meter circuit so I left them as E-caps.
I didn't see any small transistors that are known troublemakers to be preemtively replaced, maybe someone else will chime in.
I attached a pic of what I think is the correct LED replacement, search fleabay for "pioneer wedge LED"
Here is the heatsink mod from Watthour - see reply 12.

http://www.audiokarma.org/forums/showthread.php?t=363440

SX780 doesn't have a CSSA type cap, but some receivers do (like the SX750 I just did). Mark was just being his usual thorough self.
 

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Thanks for the info!...but now I have other issues with the unit. Will definitely keep for future reference when I get there! At the rate I'm going, I'm about to have a vintage paper weight.
 
You'll get it working. Meanwhile I placed my Mouser order today. There are a lot of SX780 rebuild threads right now. I don't have any repairs to do, so I might be the first to start the recap. If so, I'll make a new thread and document.
 
Found an error in the cap list referenced in the sticky
C213 47 6V cea 470/6.3V 647-UPW0J470MDD6
C214 47 6V cea 470/6.3V 647-UPW0J470MDD6

not good to replace 47uf with 470uf. The following should be fine.
47/16V 647-UPW1C470MDD

Also, Nolannniah mentioned that the following replacements hurt base and treble
C229 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C230 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL

I'll try the following film caps and see what happens.
667-ECW-FD2W225JB

Here are some pics of the rebuild. Easy accessability on this model. Pulled off one side panel to reach caps at the edge of the board. Pulled off the lower front panel to deoxit the pots and switches.
 

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Found an error in the cap list referenced in the sticky
C213 47 6V cea 47/6.3V 647-UPW0J470MDD6
C214 47 6V cea 47/6.3V 647-UPW0J470MDD6

not good to replace 47uf with 470uf. The following should be fine.
47/16V 647-UPW1C470MDD

no, the cap number is correct, the document's notation that it is 470/6.3 is the error.

The original referenced 647-UPW0J470MDD6 IS a 47uf 6.3v cap!!

a 647-UPW0J471MPD is a 470uf cap... there is no 470uf 471MDD6 cap.
good thing I have developed an eye for the numbers...
 
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Crap. My correction stands corrected. Thanks Markthefixer/memorizeroftheMousercatalog! I'll see if film caps work better for C229/30.
 
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Decided to mod Q25 with mica insulator and heatsink. The mica supplied by Mouser doesn't fit inside the "U" of the heatsink. What is the approved method of trimming mica? Exacto? Scissors? Does mica like to shatter and split? I'd hate to screw it up and waste more time waiting for a replacement.
 
I've had success cutting mica insulators with very sharp and sturdy electrician's shears (the kind used for panelboard work). The edges may craze a bit if dull scissors are used.

Be sure to use a screw bushing to insulate the steel screw, or a nylon screw.
 
Just installed the following caps

C229 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL
C230 2.2 50V ceanl 2.2/50V 647-UKL1H2R2KDDANA UKL

Sound good to me - films are usually a good choice if they fit. In this case the leads were a tight fit in the circuit board holes. I reamed them gently with an ice pick which was just enough. The physical size of the caps was also a bit dicey. One of them is sandwiched between the face plate and another cap. I had to rebend the leads to shift the cap back and away from the face, then mount it at an angle to clear the other cap. So, not a drop in replacement, but not too bad. Probably a slight sonic improvement.

I'm going to go out on a limb and hope Markthefixer doesn't critique me on this, but I think this is probably an important pair of caps. From my still newbie attempts at reading schematics these caps are the passthrough from the preamp section to the amp (just after the treble control). Should note that the signal path goes through some 4.7uF UKL caps (C218/9) just before the treble control. These are too big for films, but I wonder if 2.2uF could be subbed there as well.
 
C217, C218.

C217, C218 4.7uf 2.2 + 2.2 = 4.4 which is close, plus that location has a skosh more room to shoehorn them in to. Half the capacitance would do some bass rolloff.

C207, C208? What did you do with these, if you want a straight through polypro cap string, these too. 1uf

Then bypass c213, c214 (47uf 16v) with 1uf polypro as well.
 
I installed the entire list from post 5 including the tuner. All 1uF are Panasonic stacked film. I'll double up on the 2.2s and post result. Will include pics.
 
A photo of the film replacements for C229/30. Also some pics of the heatsink mod to Q25. I cut down an old CPU heatsink and tapped it for the machine screw included in the mica insulator kit. The original heatsink hole was enlarged. JB Weld keeps the two heatsinks secure.
 

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