SX-780 recap list ?
- Thread starter barkerd
- Start date
I am nearing completion of an sx-780. I compared the list attached to this thread but chose mostly Elna SilmicII caps when available, all from Mouser,com. Here are a couple notes.
There are actually 2 unlabeled caps,one above C309 and one above C406.
Because C325 and C326 are jumped out these values get moved to the unlabeled locations so the quantity of 4.7uf/35v is 6.
I tried the 10,000uf/50v as suggested. I ordered a Nichicon 647-UFW1H103MRD. It fit perfectly in place. It sounds really great. Whether it is better than original, I cannot say. I am not that familiar with the sx-780.
Before I put in the big caps, I tested the unit with speakers. It sounded good, but had random pops coming from center stage, and the pops changed with the volume setting. This did not occur before the changes. I kept my fingers crossed that I was witnessing the rapid degradation of the remaining caps. This turned out to be the fact, because after replacing the 10,000uf caps everything worked just fine.
There are actually 2 unlabeled caps,one above C309 and one above C406.
Because C325 and C326 are jumped out these values get moved to the unlabeled locations so the quantity of 4.7uf/35v is 6.
I tried the 10,000uf/50v as suggested. I ordered a Nichicon 647-UFW1H103MRD. It fit perfectly in place. It sounds really great. Whether it is better than original, I cannot say. I am not that familiar with the sx-780.
Before I put in the big caps, I tested the unit with speakers. It sounded good, but had random pops coming from center stage, and the pops changed with the volume setting. This did not occur before the changes. I kept my fingers crossed that I was witnessing the rapid degradation of the remaining caps. This turned out to be the fact, because after replacing the 10,000uf caps everything worked just fine.
micwood55
Active Member
Thank You for your Lists really saved this Beginner a lot of time and probably money on mistakes ordering the caps... Came out very well very happy and hope to give it to one of my kids as a gift. Now onto the bigger series have a 980 & 1050 really needed that experience to give me the confidence to even attempt recapping one of the bigger one just take your time and pay attention. My Motto is Live to Learn, Learn to Live!
Care to share some of these additions?
I see this thread has been resurrected a few times already, so I'll post this here. If I should post a separate thread, please let me know.
I was given an SX780 back in the fall and it is cosmetically in a bit rough condition, and it's dirty inside, but it at mostly works, which is great. The previous owner told me he thought it had a problem with the relay because it would shut off after playing for a bit. Given it's age and condition, I figured it could be nearly anything. I tested it out, and it had some pretty serious crackling\noise issues when adjusting volume or playing at moderate volume. I cleaned the pots for a while and eventually the static and scratching went away. The sound is noticeably distorted though and after several minutes of playing at moderate volume the speaker relay does turn off. The previous owner had already opened up the top of the relay so I tried cleaning it myself and it didn't seem to make any difference.
I mainly work with PCs but I already had several capacitors on hand that fit the bill for recapping the SX780. The rest I ordered from Mouser (all good name brand, mostly Nichicon), along with a replacement relay. I finally had time today to try replacing the relay and sadly it didn't fix the issue (I didn't really think it would). I decided to replace a few of the caps as well, so I started with the two biggest ones first (470uf 63v and 220uf 63v) and the 47uf 16v (C319) mentioned in another thread as causing problems with the relay circuit. Again, there's no obvious difference in the distorting and it still shuts off. At this point it's probably the SK-0050s but I plan on replacing the caps to improve the sound anyway.
Now is where it gets weird.
I bought a DE-5000 LCR meter a couple years ago and I'm not really educated enough to understand it completely but I felt it was a good thing to invest in. I used it to test the 40+ year old ELNA caps that I removed today and to my amazement they are still showing great specs as far as I can tell.
My question for anyone here who has a detailed knowledge of these things:
If the caps are 40 years old and the measured capacitance is actually CLOSER to the rating than the new ones I'm using, should I really be replacing them? Also, all of the other measurable specs (D, Q, ESR, ɵ ... whatever that is?) are very close to the new replacement ones. I'm a firm believer in "if it works, don't mess with it" but I assumed there would at least be a measurable and possibly audible difference between brand new and 40 year old capacitors. I have a feeling that replacing all of the caps will change the sound for the better, but if none are measuring poorly with an LCR meter, what causes the degradation in sound and why do we replace them? Is there a specific way I should be testing these that will show me that they are 40 years old and should be replaced?
... and finally, is there any other specific capacitor or other component I should check before going straight to the SK-0050s? It looks like at least one was replaced once already. Also, they don't have the same exact pins soldered... I'm wondering if it had a bad repair job at some point?
I was given an SX780 back in the fall and it is cosmetically in a bit rough condition, and it's dirty inside, but it at mostly works, which is great. The previous owner told me he thought it had a problem with the relay because it would shut off after playing for a bit. Given it's age and condition, I figured it could be nearly anything. I tested it out, and it had some pretty serious crackling\noise issues when adjusting volume or playing at moderate volume. I cleaned the pots for a while and eventually the static and scratching went away. The sound is noticeably distorted though and after several minutes of playing at moderate volume the speaker relay does turn off. The previous owner had already opened up the top of the relay so I tried cleaning it myself and it didn't seem to make any difference.
I mainly work with PCs but I already had several capacitors on hand that fit the bill for recapping the SX780. The rest I ordered from Mouser (all good name brand, mostly Nichicon), along with a replacement relay. I finally had time today to try replacing the relay and sadly it didn't fix the issue (I didn't really think it would). I decided to replace a few of the caps as well, so I started with the two biggest ones first (470uf 63v and 220uf 63v) and the 47uf 16v (C319) mentioned in another thread as causing problems with the relay circuit. Again, there's no obvious difference in the distorting and it still shuts off. At this point it's probably the SK-0050s but I plan on replacing the caps to improve the sound anyway.
Now is where it gets weird.
I bought a DE-5000 LCR meter a couple years ago and I'm not really educated enough to understand it completely but I felt it was a good thing to invest in. I used it to test the 40+ year old ELNA caps that I removed today and to my amazement they are still showing great specs as far as I can tell.
My question for anyone here who has a detailed knowledge of these things:
If the caps are 40 years old and the measured capacitance is actually CLOSER to the rating than the new ones I'm using, should I really be replacing them? Also, all of the other measurable specs (D, Q, ESR, ɵ ... whatever that is?) are very close to the new replacement ones. I'm a firm believer in "if it works, don't mess with it" but I assumed there would at least be a measurable and possibly audible difference between brand new and 40 year old capacitors. I have a feeling that replacing all of the caps will change the sound for the better, but if none are measuring poorly with an LCR meter, what causes the degradation in sound and why do we replace them? Is there a specific way I should be testing these that will show me that they are 40 years old and should be replaced?
... and finally, is there any other specific capacitor or other component I should check before going straight to the SK-0050s? It looks like at least one was replaced once already. Also, they don't have the same exact pins soldered... I'm wondering if it had a bad repair job at some point?
I have HEARD improvements that I could NOT quantify or justify with my current test equipment. old vs. new electrolytic caps.
This was verified using double blind testing.
e-caps are complex beasts whose interactions only APPROXIMATE what we see as operational curves.
Cripes, I have had TRANSISTORS that tested good, yet sounded crappy, and when replaced by a992's and C1845's made a startlingly better "sound" that even uninformed stone noobs noticed without prompting.
And again, without using test equipment necessitating a second mortgage, I couldn't spot WHY.
This was verified using double blind testing.
e-caps are complex beasts whose interactions only APPROXIMATE what we see as operational curves.
Cripes, I have had TRANSISTORS that tested good, yet sounded crappy, and when replaced by a992's and C1845's made a startlingly better "sound" that even uninformed stone noobs noticed without prompting.
And again, without using test equipment necessitating a second mortgage, I couldn't spot WHY.
So, I am recapping my SX780 using the caps I ordered many months ago and now I see that the cap list uploaded more than 10 years ago has a typo...
It says for C227,C228 to get "647-UKT1HR33MDD" but these are .33uf caps, not 0.22uf. I apparently didn't notice this at the time so I now have two of the .33uf caps on hand and no .22. Too bad, I just made another Mouser order yesterday and didn't know I needed these. Also, .22uf 50v UKT are back-ordered there now so I'll probably need to make yet another order from digikey at some point...
If this is a typo, can someone fix the documents uploaded in those posts? I've seen other posts mentioning this discrepancy as well, but no explanation as to whether this is intentional or not. I wonder how many people have ordered the wrong ones over the years after reading this... LOL
It says for C227,C228 to get "647-UKT1HR33MDD" but these are .33uf caps, not 0.22uf. I apparently didn't notice this at the time so I now have two of the .33uf caps on hand and no .22. Too bad, I just made another Mouser order yesterday and didn't know I needed these. Also, .22uf 50v UKT are back-ordered there now so I'll probably need to make yet another order from digikey at some point...
If this is a typo, can someone fix the documents uploaded in those posts? I've seen other posts mentioning this discrepancy as well, but no explanation as to whether this is intentional or not. I wonder how many people have ordered the wrong ones over the years after reading this... LOL
mgrisoli
Active Member
I have been using someone else's list for receivers and I notice that we need some documentation for the Pioneer SX-780.
So here is my contribution to this forum...
My list replaces all capacitors <=4.7uF with WIMA filter capacitors and has mouser part #s (contingent on what was available today).
Capacitors >4.7uF are mostly from Nichicon UPW series.
It includes the main filter caps, so please check first if you really need to replace them.
I found at least 5 capacitors that are documented in the diagram and actually exist in the receiver but were not part of the original list I found here, not sure why.
I have also photographed and marked the position of all capacitors (before recap)
AWE-099
GWK-118 - left side
GWK-118 right side
Of course... this is the version I am working on.
Every time we open one of these receivers there is chance they will be slightly different from each other.
But at least you can now just concentrate on finding the differences...
I don't feel in condition to mentor anybody on recapping receivers, but at least I can share what I am doing and hope it may be useful to somebody else.
Cheers!
So here is my contribution to this forum...
My list replaces all capacitors <=4.7uF with WIMA filter capacitors and has mouser part #s (contingent on what was available today).
Capacitors >4.7uF are mostly from Nichicon UPW series.
It includes the main filter caps, so please check first if you really need to replace them.
I found at least 5 capacitors that are documented in the diagram and actually exist in the receiver but were not part of the original list I found here, not sure why.
I have also photographed and marked the position of all capacitors (before recap)
AWE-099
GWK-118 - left side
GWK-118 right side
Of course... this is the version I am working on.
Every time we open one of these receivers there is chance they will be slightly different from each other.
But at least you can now just concentrate on finding the differences...
I don't feel in condition to mentor anybody on recapping receivers, but at least I can share what I am doing and hope it may be useful to somebody else.
Cheers!
Its the year 2021, and I am still benefited from your awesome list and the remarkable feedback in this topic. Thank you guys!
Jamesvintage
New Member
Just saw this post and I am just starting on my SX-780. This will be my first rebuild/restore so current list would be very helpful to compare against older lists. However, I don't see the attachment. Would you be kind enough to point me to the list or PM it to me? Thanks
mgrisoli
Active Member
This is the one I used a couple years ago.
It might need some work since Mouser stock is low in some of these...
# Circuit Board Reference Wanted Capacitance Wanted Voltage (V) Note Mouser Part
1 Capacitor Assembly GWR-110 C501 8000 63 647-LKS1J822MESB
2 Capacitor Assembly GWR-110 C502 8000 63 647-LKS1J822MESB
3 Power Amplifier GWK-118 C103 2.2 50 505-MKS22.2/50/10
4 Power Amplifier GWK-118 C104 2.2 50 505-MKS22.2/50/10
5 Power Amplifier GWK-118 C105 470 6.3 647-UPW0J471MPD
6 Power Amplifier GWK-118 C106 470 6.3 647-UPW0J471MPD
7 Power Amplifier GWK-118 C117 2.2 50 505-MKS22.2/50/10
8 Power Amplifier GWK-118 C118 2.2 50 505-MKS22.2/50/10
9 Power Amplifier GWK-118 C201 4.7 50 505-MKS2B044701K00MO
10 Power Amplifier GWK-118 C202 4.7 50 505-MKS2B044701K00MO
11 Power Amplifier GWK-118 C207 1 50 505-MKS2B041001C00KS
12 Power Amplifier GWK-118 C208 1 50 505-MKS2B041001C00KS
13 Power Amplifier GWK-118 C213 47 6.3 647-UPW0J470MDD6
14 Power Amplifier GWK-118 C214 47 6.3 647-UPW0J470MDD6
15 Power Amplifier GWK-118 C217 4.7 25 505-MKS2B044701K00MO
16 Power Amplifier GWK-118 C218 4.7 25 505-MKS2B044701K00MO
17 Power Amplifier GWK-118 C227 0.22 50 505-MKS20.22/63/10
18 Power Amplifier GWK-118 C228 0.22 50 505-MKS20.22/63/10
19 Power Amplifier GWK-118 C229 2.2 50 505-MKS22.2/50/10
20 Power Amplifier GWK-118 C230 2.2 50 505-MKS22.2/50/10
21 Power Amplifier GWK-118 C301 100 25 647-UPW1E101MED1TD
22 Power Amplifier GWK-118 C302 100 25 647-UPW1E101MED1TD
23 Power Amplifier GWK-118 C303 100 25 647-UPW1E101MED1TD
24 Power Amplifier GWK-118 C304 100 25 647-UPW1E101MED1TD
25 Power Amplifier GWK-118 C305 47 35 647-UKT1V470MDD
26 Power Amplifier GWK-118 C306 47 35 647-UKT1V470MDD
27 Power Amplifier GWK-118 C307 100 50 647-UPW1H101MPD
28 Power Amplifier GWK-118 C308 100 50 647-UPW1H101MPD
29 Power Amplifier GWK-118 C309 2.2 50 505-MKS22.2/50/10
30 Power Amplifier GWK-118 C309B 4.7 50 No in diagram but exist in the receiver 505-MKS2B044701K00MO
31 Power Amplifier GWK-118 C310 2.2 50 505-MKS22.2/50/10
32 Power Amplifier GWK-118 C311 220 16 Diagram is wrong this is 220uF 647-UPW1C221MPD
33 Power Amplifier GWK-118 C314 470 63 647-UPW1J471MHD6
34 Power Amplifier GWK-118 C315 220 63 647-UPW1J221MPD6
35 Power Amplifier GWK-118 C316 47 50 647-UPW1H470MED
36 Power Amplifier GWK-118 C317 33 16 647-UPW1C330MDD
37 Power Amplifier GWK-118 C318 10 16 647-UPW1C100MDD
38 Power Amplifier GWK-118 C319 47 16 647-UPW1C470MDD
39 Power Amplifier GWK-118 C324 4.7 50 505-MKS2B044701K00MO
40 Power Amplifier GWK-118 C325 4.7 50 505-MKS2B044701K00MO
41 Power Amplifier GWK-118 C326 4.7 50 505-MKS2B044701K00MO
42 Power Amplifier GWK-118 C327 4.7 50 505-MKS2B044701K00MO
43 Power Amplifier GWK-118 C401 0.47 50 505-MKS2B034701B00JS
44 Power Amplifier GWK-118 C402 0.47 50 505-MKS2B034701B00JS
45 Power Amplifier GWK-118 C403 0.47 50 505-MKS2B034701B00JS
46 Power Amplifier GWK-118 C404 0.47 50 505-MKS2B034701B00JS
47 Power Amplifier GWK-118 C405 10 16 647-UPW1C100MDD
48 Power Amplifier GWK-118 C406 220 6.3 647-UPW0J221MED
49 Tuner AWE-099 C027 2.2 50 505-MKS22.2/50/10
50 Tuner AWE-099 C028 4.7 50 505-MKS2B044701K00MO
51 Tuner AWE-099 C034 1 50 505-MKS2B041001C00KS
52 Tuner AWE-099 C035 22 16 647-UPW1C220MDD6
53 Tuner AWE-099 C037 6.8 6.3 647-UPW2A6R8MDD1TA
54 Tuner AWE-099 C038 1 50 505-MKS2B041001C00KS
55 Tuner AWE-099 C040 1 50 505-MKS2B041001C00KS
56 Tuner AWE-099 C041 1 50 505-MKS2B041001C00KS
57 Tuner AWE-099 C043 220 16 Diagram is wrong this cap is 220uF 647-UPW1C221MPD
58 Tuner AWE-099 C044 220 16 647-UPW1C221MPD
59 Tuner AWE-099 C053 220 16 647-UPW1C221MPD
60 Tuner AWE-099 C060 4.7 50 505-MKS2B044701K00MO
61 Tuner AWE-099 C061 3.3 50 505-MKS2B043301H00KI
62 Tuner AWE-099 C071 10 16 647-UPW1C100MDD
63 Tuner AWE-099 C076 10 16 647-UPW1C100MDD
Last edited:
Chris Pylant
New Member
I'm also just starting a SX-780 repair/refurb. Your effort with the capacitors is greatly appreciated!!
Great post, guys! I've been using my 780 for about 6 months now, and all I had to do was clean it up and replace the dial light lamps after I brought it up on my variac. It's my main "Shop" receiver while I finish up my 980, and then I'll go through the 780.
The lists and advice are invaluable to a rookie with a Pioneer Silver Series!
The lists and advice are invaluable to a rookie with a Pioneer Silver Series!
I have a question regarding the filter capacitors, please excuse my lack of knowledge for asking
Why did you solder a wire between the terminals
It was my understanding that the capacitor has a + and - leads or terminals , the center terminal is dummie post to stabilize the capacitor .
I’m kinda confused of how these terminals are supposed to be soldered , I do plan on using the capacitors you install the Nichicon KG Gold .
Also what were the values of the filter caps you installed , could not find it in your list unless I over looked it
Thank you kindly
Bernard
Why did you solder a wire between the terminals
It was my understanding that the capacitor has a + and - leads or terminals , the center terminal is dummie post to stabilize the capacitor .
I’m kinda confused of how these terminals are supposed to be soldered , I do plan on using the capacitors you install the Nichicon KG Gold .
Also what were the values of the filter caps you installed , could not find it in your list unless I over looked it
Thank you kindly
Bernard
The schematic shows 2-each terminations per filter capacitor C501 and C502
Attachments
mgrisoli
Active Member
Hi Bernard,
Filter caps for SX-780 are originally 8000mF / 50v, in the list I shared on the post #32 they are #1 and #2 in the list.
The suggested replacements caps are snap-in with two leads each, 63v instead of 50v.
I think 647-LKS1J822MESB is a drop in replacement, if my memory doesn't fail me.
Electrolytic caps have a positive and a negative lead, that is true, there are several reasons for caps to have more than two leads, but a common one is to have dummy pins for mechanical attachment. But, in some cases, they have polarity as well, you need to refer to the datasheet of the cap you are looking to understand the function of each lead.
Filter caps work in conjunction with the rectifier bridge to produce + and - DC voltage for the equipment to function. The positive lead of one of the caps will provide +65v and the negative lead of the other cap will provide -65v (which is half of AC 127v!), the other two leads of each cap are connected to each other and to the chassis providing 0V.
Filter caps for SX-780 are originally 8000mF / 50v, in the list I shared on the post #32 they are #1 and #2 in the list.
The suggested replacements caps are snap-in with two leads each, 63v instead of 50v.
I think 647-LKS1J822MESB is a drop in replacement, if my memory doesn't fail me.
Electrolytic caps have a positive and a negative lead, that is true, there are several reasons for caps to have more than two leads, but a common one is to have dummy pins for mechanical attachment. But, in some cases, they have polarity as well, you need to refer to the datasheet of the cap you are looking to understand the function of each lead.
Filter caps work in conjunction with the rectifier bridge to produce + and - DC voltage for the equipment to function. The positive lead of one of the caps will provide +65v and the negative lead of the other cap will provide -65v (which is half of AC 127v!), the other two leads of each cap are connected to each other and to the chassis providing 0V.
Thank you so much for all the info
I really appreciate all your help
I bought the Nichicon Gold Capacitors. 8200 mfd, 50vdc. Very close to the original specs ,
10 mm spacing between the terminals .
The original Elna’s as you mentioned are 3 terminal , not 2 like the replacement Nichicon, but the spacing between the + and - on the PCB board is longer than 10mm.
So I guess I can use the center (dummie) hole on the PCB to secure the capacitor, then bend the length of the terminal over to reach the negative center lan on the PCB board .
Does that kinda make any sense , or do I have it all wrong .
I’ve attached some of your pics from your project and capacitor I purchased .
Thanks
I really appreciate all your help
I bought the Nichicon Gold Capacitors. 8200 mfd, 50vdc. Very close to the original specs ,
10 mm spacing between the terminals .
The original Elna’s as you mentioned are 3 terminal , not 2 like the replacement Nichicon, but the spacing between the + and - on the PCB board is longer than 10mm.
So I guess I can use the center (dummie) hole on the PCB to secure the capacitor, then bend the length of the terminal over to reach the negative center lan on the PCB board .
Does that kinda make any sense , or do I have it all wrong .
I’ve attached some of your pics from your project and capacitor I purchased .
Thanks
Attachments
mgrisoli
Active Member
Ok, it seems the voltage coming out of the caps is +-40v, so your choice for the 50v caps would fit.
For next time the advice is to go up a notch, perhaps 65v. Remember that voltage in US used to be 110v then it got to 127v and that WILL reflect proportionally on the transformer secondary wiring.
Your idea of bending the leads to make them reach the existing holes make work if the bended leads do not prevent the capacitor of properly sitting on the board.
You may also check if you can punch a couple new holes in the PCB that would respect the lead spacing of the new caps.
As long as you connect the right polarity with the proper tracks you would be fine.
