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Pioneer SPEC-2 recap and restoration thread!

Thank you! Yes, duh, KSC945

I am pretty sure I have the 945, but not so sure about the 733. I may have used them in another project, but I cannot recall. I have not found all my caps and transistors as yet, I moved house recently. If not, I will go for the KSA1015/KSC1815 pair instead.

Cannot wait to get my hands on the beast that is the M-77!
 
Thank you so much for the Info@mattsd

I recently got my hands on an old SPEC 2 and as the Right CH has distortions in the Highs i would like to Rebuild it starting with the Power AMP curcuit. Regarding Q1, would there be a major drawback in using "new" original 2SA798-G/F instead of your two KSA992FBU? As i am not comfortable dealing with gain matching and really would like to not ruin the Project because of that.
 
As far as substituting the 2SA798-G/F with a KSA992FBU, the 992 is an appropriate equivalent replacement for the 798. Much easier to find if I had to guess.
As a far matching the 992s, just buy a cheap Chinese component tester from the big auction site and buy about 20 or 30 992s from Mouser or Digi-key then test them.
20231203_235558.jpgThe tester will report the hFE of each transistor. You just need to find 2 that have the same hFE values. Not uncommon.
 
This 2SA798 replacement question should probably have its own thread, but the reason gain matched KSA992's have replaced them for many years is that original, high quality, 2SA798's are no longer manufactured (or available). The auction site shows many so-called "2SA798's" available from China at crazy high prices (especially when compared to KSA992's), but I would NOT trust them. They don't even look like the original 2SA798's. A US based seller is now also offering these as "US Stock", but they look exactly like the ones being sold out of China, which I believe they are.

If anyone has definitively proven, technically, that these Chinese replacements are the same quality as the original 2SA798's, or even the gain matched KSA992's, please let us all know. Otherwise I wouldn't touch any of these Chinese knock off's with a 39-and-a-half-foot pole (I just watched "The Grinch" the other day).
 
mattsd said:
Got the micas and we're back in business!

Here is the left channel outputs after, all new micas and thermal paste.

roZCpet.jpg


Now for the right channel. The STV diodes were all original on this board, but it still had questionable cap and transistor replacements. Some of the transistors were replaced with the correct On-Semi MJEs however.

URFPc9Z.jpg


And after! All the molex pins were cleaned and all the other replacements parts are the same as the left channel.

a5XF7FV.jpg


The left channel outputs were good originals, but in the interest of symmetry, I replaced them as well with the On-Semi MJ outputs

w0bIlFS.jpg


And after:

6CoLhIq.jpg


Next post will be the power supply and the meter amp board. It's coming along somewhat slowly as I have a 1280 I'm doing concurrently which I'll also be posting here as I do not believe there is a complete restore thread on a 1280. More to come!
Click to expand...

Hi Matt, first of all real nice restore job you have done :)

I am in the process of restoring my own Spec-2 and I am replacing the O/P transistors with the same parts as you did MJ21195G/MJ21196G.

I was just wondering, if you could inform if you have set the idle current to 30mV according to the service manual, or did you set it differently with these replacement O/P's. At what value, did you set your idle current?

Also, did you push the current limiter differently that according to the service manual, since these MJ21195G/MJ21196G are somewhat more powerfull than the original parts. At what value, did you set your current limiter?

Regards/Michel
 
MThomsen said:
Hi Matt, first of all real nice restore job you have done :)

I am in the process of restoring my own Spec-2 and I am replacing the O/P transistors with the same parts as you did MJ21195G/MJ21196G.

I was just wondering, if you could inform if you have set the idle current to 30mV according to the service manual, or did you set it differently with these replacement O/P's. At what value, did you set your idle current?

Also, did you push the current limiter differently that according to the service manual, since these MJ21195G/MJ21196G are somewhat more powerfull than the original parts. At what value, did you set your current limiter?

Regards/Michel
Click to expand...
I set everything according to the service manual I didn't change anything.
 
MThomsen said:
Thanks Johnny, are you also using MJ21195G/MJ21196G as o/p units?
Click to expand...
I'm not sure I didn't take a picture of it when it was completed that I can find. Here's the thread on all the parts I used when I redid the spec 2.

Pioneer SPEC-2 Left Power AMP is VERY HOT and Right Power AMP is cool.

Pioneer SPEC-2 Left AMP is very hot and Right is nice and cool. I have the SPEC-2 on the bench tuning it up. The Left Power APM gets hot just turned on with a signal on the input from a CD player I use for testing, volume levels at 0, no speakers attached. And again, just one side is hot--very...
audiokarma.org
 
Hello everyone and Happy Holidays! ⛄️

I know this is an old thread but... I was using the parts list to order from Digikey and quite a few of the parts are obsolete :-(
Can anyone please provide an updated list of parts? Thanks in advance.

Cheers
 
Hello everyone,

I'm currently shopping for all the parts to recap my Pioneer Spec-2 and I'm finding some parts are hard to find or obsolete... say for instance part "ECQ-E2106KFB" is only sold in bags of 1000

Can someone please let me know where to find these caps? Thanks in advance.

Cheers,
Rod.
 
rctm said:
Hello everyone,

I'm currently shopping for all the parts to recap my Pioneer Spec-2 and I'm finding some parts are hard to find or obsolete... say for instance part "ECQ-E2106KFB" is only sold in bags of 1000

Can someone please let me know where to find these caps? Thanks in advance.

Cheers,
Rod.
Click to expand...
Just get film cap with the same lead pitch. However, do you really even need to replace them? Film cap are only damaged when there's an actual defect or was hit with surge. They don't have a "Kaput-by-date" like electrolytic caps do.

Please look up the reason to recap before you recap.
 
rctm said:
@zycamaniac I appreciate your input but, what I asked for was reference of where I can get my hands on a specific part :)
I'm just trying to follow up on the work done by @mattsd

​

Click to expand...
Ah, my apologies. The replacement for that bipolar bypass cap for power input.

Just any normal film cap rated at 160V and up at the same capacity will work. (no X caps or Y caps or other "safety" caps) You will just need to figure out how to shoehorn it into place.
 
The ECQ-E2106KFB is still available on Mouser in single quantity, $3.66 per as of this post. Digi-Key doesn't stock a lot of parts that Mouser does and the list is made for Mouser. I just updated the list to replace obsoleted parts
 
mattsd said:
The ECQ-E2106KFB is still available on Mouser in single quantity, $3.66 per as of this post. Digi-Key doesn't stock a lot of parts that Mouser does and the list is made for Mouser. I just updated the list to replace obsoleted parts
Click to expand...
Thanks @mattsd much appreciated... I'll start placing my order with Mouser.

Cheers
 
I think I may have modded the case. Refresh my memory where the ARS-028 (LY2-DC48) relay is in the Spec2. I still have it I will look.
 
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