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Pioneer SX-D7000 - another adventure in recapping

w1jim

w1jim

I can fix it but good...
Subscriber
Honestly, I never intended on recapping my SX-D7000.

But after I recently recapped my SX-1980 I was goaded (motivated?) on by bbauer01 to compare them with my A/B comparator I recently built for my SX-850 comparison at our New England get together.

These are both TOTL receivers for their years so I figured the newer D7000 would be better or at least the equal of the 1980. Not to be - the 1980 had a clarity that the D7000 was missing. Not that the D7000 sucked - it's just that the 1980 was (to my ears) a little bit better.
Damn, time to get crackin'.

So far I've recapped the amplifier PCB (the vertical one) and the tuner PCB.
I replaced 2 - 0.22uf electrolytics with poly film caps (they're the little red ones) and replaced the 2 - 4.7uf electrolytics on the input with some higher grade Nichicon "Muse" caps - the greenies.

On the tuner PCB I've replaced 14 electrolytics of 1.0uf and below with the poly film caps and all of the electrolytics.
One of the caps on the tuner board was a 2.2uf (C114 I think) but it looked like the decimal point was an afterthought. I measured the old part (1.85uf) and looked at the schematic to confirm it's value.

Next week, I'll start addressing the front PCBs.

I've been saving all of the parts and will create an inventory upon completion - something that is missing from the downloadable service manuals.



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Don't forget to upgrade the power transistor connectors, and the 4 current regulator transistors on the corner(s) of the amplifier board to to-126's...

You may want to bypass those input caps on the amp with 0.22uf stacked films, the same type as you should be using on the overcurrent protection circuit in the center of the amplifier board.
 
I will be following this thread.

W1jim: I am glad I "motivated" you. Before anyone can call me a copy-cat, I will call you a great leader, since I will be following in your footsteps. First my SX-1980, next my SX-D7000. Good luck with this one.
 
Back from my work-weekend in Memphis, washed the last of the BBQ sauce off my stcky fingers and got back to the D7000.

Things aren't all that hard to get to once you cut a few wire ties and unscrew the face and PCBs.

Recapped the Phono amp PCB and throughly deoxit'ed the switches.
The 2 large green Nichicon Muse caps (4700uf / 16 volts) replaced the original 3300uf / 10 volt caps. I had these on hand and they seemed like a nice upgrade although I doubt there would be much if any sonic difference.



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Making progress.

I have most of the tone / volume and power supply PCBs recapped but am waiting on some parts.
The tone board uses 4 - 0.15uf caps which are an unusual value so those are on order as well as some larger caps for the PS. I'm using poly film caps in place of the original "LR" electrolytics.

I also ordered 8 replacement 3 pin connectors to use on the amplifier power transistors. The original ones that are in there seem to be in good shape but since these tend to be a problem area I might as well go for the upgrade. I usually order my parts from mouser.com but decided to piggyback these with an order I had with Newark.com. Here's a link to the part (available from either source).
http://www.newark.com/jsp/search/productdetail.jsp?SKU=71C4153

Finished up the 2 flouroscan display boards and replaced the red LEDs with brighter more modern parts.




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Just curious... How are you choosing your caps? I see that you are using various different Nichicon caps. I see some VZ, KW, KG/Muse, and what looks to be some PWs. Are you choosing based on your current stock, or do you choose caps based on the different spec caps that Pioneer used (i.e. cea / ceanl)?
 
Certainly part of it has to do with wha I have in stock but generally I try to use the FG, KW and KG in the audio path and will use "lesser" caps in power regulation circuitry. In non-audio circuits (like the flouroscan and power supply) I've used some Sanyo caps rated at 105C as well as some Panasonics.
Very often it's less science and more convenience. I'm of the opinion that most modern caps are superior to the "better" old caps. As previously mentioned I'll use poly film caps in the audio path to replace 1uf or less electrolytics.
JimB
 
the only electrolytic that is low leakage (ceanl, cssa, csza) is the ukl. what other gains the FG, KW and KG might supply, are most likely lost in the increased noise.
 
markthefixer said:
the only electrolytic that is low leakage (ceanl, cssa, csza) is the ukl. what other gains the FG, KW and KG might supply, are most likely lost in the increased noise.
Click to expand...
MTF-
Do you think there will be a discernible difference by my using the Nichicon audio-grade (FG/KW/KG) series caps to replace the Pioneer low leakage caps instead of the KL series? I have not used the KL's.
I've been under the impression that the caps I've been using are equal or superior to the original low leakage parts.
 
w1jim said:
MTF-
Do you think there will be a discernible difference by my using the Nichicon audio-grade (FG/KW/KG) series caps to replace the Pioneer low leakage caps instead of the KL series? I have not used the KL's.
I've been under the impression that the caps I've been using are equal or superior to the original low leakage parts.
Click to expand...

Here is what I had written in my notes regarding caps, Mark chime in and correct me if my notes are wrong...

Nichicon leakage Specs:
FG => 0.01CV
PW => 0.03CV
KL => 0.002CV

Pioneer spec for the caps is:

ceanl => 0.003CV
cea => 0.03CV
 
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Nichicon is not very forthcoming about the whats and whys of why audio grade caps versus upw and ukl caps.

I do know that upw's have significantly longer life expectations. ukl for lower leakage even though their life expectation is shorter and they are 85 degree c parts. I have demonstrated to my own satisfaction the need for lower leakage parts in some circuit positions.

the only caps that I have found that tell WHY they are more suited for audio is the silmic2's.
sil = silk fibers in the separator for better capacitance consistency, and greater resistance to (mic = ) microphonics - both of which I will have to take their word for. For example: Can one HEAR the difference in microphonics that are 60 db down versus 70 db down (off the top of my head)? At that sound level, I personally doubt it.

sometimes higher end parts have absolutely NO iron in them, a lot of leads are copper plated and the clipped off leads can be picked up with a magnet - indicating some type of magnetic content. Pioneer makes some mention of this ("magnetic distortion") in their MARKETING material.... and to me marketing material = exaggerations wrapped around a thin core of physics based truth, with all the bad and inconvenient parts purposefully omitted.

it would help to SAY why they are audio caps - like perhaps 5% better(less) dielectric adsorption, for example... but they don't. maybe they just want to build a "following" built on faith. I believe that's called marketing.
 
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markthefixer said:
Don't forget to upgrade the power transistor connectors, and the 4 current regulator transistors on the corner(s) of the amplifier board to to-126's...

You may want to bypass those input caps on the amp with 0.22uf stacked films, the same type as you should be using on the overcurrent protection circuit in the center of the amplifier board.
Click to expand...
Not sure which transistors you're referring to as the current regulator transistors to upgrade to TO-126 packages. There are 2SC1915 (KSC2310) and 2SA750 KSA992) in the upper corners but the replacements in parenthesis are TO-92 packages. Are those the ones you're referring to? I don't think you mean the driver transistors; they're TO-220 packages.
Power transistor connectors are on the way.

I bypassed the input caps with the 0.22uf films as suggested.

Tnx -
JimB
 
Q115, Q116 2sa905
Q109, Q110 2sc1915

both have thick center collector leads to carry away heat, and Pioneer DIDN'T provide thick traces to do anything with the heat, thus they get HOT and crack or crystallize their solder joints over time, borking up the amp.

I used:
512-KSA1220AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.39 (R=60-120, O=100/200, Y=160/320)
512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40


those 4 dissipate the most heat, then there are 4 to-92's that get warm but are OK, and 4 itty bitty transistors that don't get hot at all.

I believe that this, along with the output transistor connectors are the PM (preventative maintenance ) key to longevity in these amps (as long as the wave solder wasn't too thin and other joints are cracking - then I resolder the board).

TO-220 driver replacements are:
757-2SA1930(Q,M) pnp to-220 bce 180v 2a 20w 200mhz 50-320hfe 200mhz nsa driver
757-2SC5171(Q,M) npn to-220 bce 180v 2a 20w 200mhz 50-320hfe 200mhz nsa driver
 
Not necessarily, I'm doing mine because I'm obsessive and I've detected that my newly recapped SX-1980 is superior and wanted to see how this exercise would improve the D7000.
I figure that at 30 or so years of age it couldn't hurt.
I don't know your level of experience but I wouldn't suggest messing around with one of these if you didn't have some previous experience.
YMMV as they say.
 
I would pop the bottom panels and look at the power output transistor connectors for cracks. We have an easy to install fix for that now. The replacement part from mouser (651-1757022 Phoenix Terminal Blocks) costs about ~ $2.20 per transistor.

They used decent quality nichicons in them, so it's nowhere near as urgent as say a 990 or a 828..

Plus their power amps are almost completely DC coupled so there's just the input cap in a slightly cooler area.

Couple that with the complexity of the eq amp and preamp board installations behind the front panel, and I would rate it at a somewhat higher level of difficulty unit(s).

Power supplies, I haven't seen may failures yet, but they still bear investigating as to board colors on the 7000's accessible to me.

Since yours aren't popping in and out of protect, they probably don't have the cracked solder joints, or (hopefully) cracked power output transistor connectors.

Leave it be.... enjoy.....

I do reserve the right to update my opinion after I work deeper (and maybe discover "tricks") on my three 7000's, two 7000's that belong to others, and the parts unit 7000. All of which are currently in house.... :scratch2:
 
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Back from a week of "tradeshow hell" in Las Vegas.

Came home to find a box of goodies from Mouser so time to get back to work on the SX-D7000.

I replaced the orange caps (that I had previously replaced) in the phono preamp and tone control circuitry with Nichicon KL / low noise capacitors.

Next, finished off the power supply PCB (pictured) and replaced 4 of the 8 power transistor connectors. Even though mine didn't look heat damaged I thought this would be a good precaution.

Next up this week will be replacing some transistors on the power amplifier PCB and putting it all back together for the adjustments.



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