Spec 1 and 2 restoration

zebulon1

Working on my own stuff. Finally
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I bought these on an ebay auction. The catch was local pick-up only, located in Socal's Inland Empire. The listing seller claimed they were inop. I went through the start-up procedures and all seemed good. Hooked them up and Bam! They work! Pots need a good cleaning but other then that Tony Bennett never sounded so good.

I Made a mouser order for the rebuild package last week in anticipation (Thanks Mark and Matt!) and will begin this resto this weekend. Lately I have been messing with the lower watt Pioneer sets of the late 60's and early 70's. Going back to the Monsters is a trip. I feel good about this as I reached a milestone in my experience in working on most of the popular Pioneer sets. All are wonderful pieces of memories and history.

The Spec's a few years ago seemed so far away for me but here they are sitting on the bench getting ready to start a second life.

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Damn, nice pick up. They look to be in great shape. I got my own work cut out for me too this weekend. Good luck!
 
Welcome to the next level.

But, you've done SX-1980 so you ain't so little time.

And hurry up! I have this SX-9000 to restore and you really NEED to do one of those to earn your merit badge!

Then we'll talk about doing a quad unit....
 
It was actually fellow Las Vegas AK'er, "blhagstrom" (See above ;-) ) who turned me on to the listing. It looks as though the seller had them sold but the buyer never came up with the payment so it was relisted. My guess was probably over the local pick-up deal. Anyway, they're here and I'm debating as to which one I start on. Both are fairly daunting.
 
The Thumb drive from Rick came today. All I can say is "Holy S!@t"! It's got tons of Pioneer stuff I've had never seen before. If you don't hear from me in the next year you'll find me in front of the computer still going through the files. :nutz: What a nice treat.

Looking forward to using the Spec Hi Res files in the next weeks. :thmbsp:
 
The Thumb drive from Rick came today. All I can say is "Holy S!@t"! It's got tons of Pioneer stuff I've had never seen before. If you don't hear from me in the next year you'll find me in front of the computer still going through the files. :nutz: What a nice treat.

Looking forward to using the Spec Hi Res files in the next weeks. :thmbsp:

Rick put together an amazing collection of Pioneer documentation and it is mind boggling. A few years ago when I reentered the audio world I would go with the free stuff but Rick has assembled a suite of Pioneer documentation that is over the top. I try to support his amazing effort when I can.

Good luck with the Spec resurrection!

Nav
 
I forget the details but it was talk of SPEC prices here in a thread that made me look in ebay and spot these.

The Audio gods brought all the pieces together in a mysterious way.
 
I kind of finished the first amp board. All except cleaning the Molex connector pins and the 100 ohm current limiting trimmers. Mouser order in the works anyway. I thought I had everything I needed. :dunno:
The way the circuit is constructed, I need the 100 ohm trimmers, no getting around it. I left the original trimmers in for now. I mapped them for resistance and plan to reinstall; and adjust to the recorded values. I have the equipment to set the current limiter sensitivity but would like any advice/experience in this procedure. :yes: Any help is greatly appreciated. :thmbsp: (I'm scouring past posts as you read this)

Replaced all the transistors and diodes using two 17v zeners for the 34v single zener and using the 1N4148's for the rest. The new KSA733 are EBC, so I installed them accordingly. Gain matched perfectly two KSA992's for the Q1 matched pair. This restore info was from several Spec 2 threads. Thanks MTF, EW, Matt and the others before me.

It took a little over four hours to get this far. If a guy was more organized he could improve it surely. I was scrounging for parts I had on hand, overstock from many other Pioneers and that took so time.

Another note: The anodizing on the heatsink doesn't like "Simple Green". Use soap and water.

The below image is the almost completed board. The second is a image of an unmolested, Spec Amplifier board.

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Yes, I just read a thread this afternoon. I thought I had ordered every thing I needed for this project but it looks like all I ordered has the stuff for the Spec 1. It was a thread Mark had helped on (Of course) and he had a part number from Digikey for them. See bottom of text.

Ok then, let's get to work, this could be fun.... having a well equipped EE on the other end of the line.... :D

(I was an Embedded Software / Hardware guy most of my career - where the software / hardware line blurs )

I have been working with excel spreadsheets for parts specifications. Transistors are covered below, but we have to do the caps. While I could generate the spreadsheet myself in an hour or three, I;m using the time to bring a SX-1980 back from the dead, a real basket case.... and it's just about ready for the world... including NEW outputs.

So, since I have saved you a lot of "transistor time". perhaps you can save me some "capacitor time"...

The information used below comes off the parts lists in the service manual.

first cell is the aaa-nnn board number
second cell is the parts designation c1,q4 etc...
third cell for transistors would be the 2s..... part number.
third for capacitors would be microfarads
fourth for capacitors would be voltage
fifth would be the special designation
(examples:
cea radial general purpose - replaced by nichicon upw, uhe Panasonic .. and ..
ceb axial general purpose nichicon tvx
ceanl low leakage electrolytic (lower noise) nichicon ukl
cssa the UBER dreaded sky blue sanyo capistor solid aluminum electrolytics
csza the dreaded tantalum caps, nichicon ukl
and others)

using those specs in the excel file as my input data (which REALLY speeds things up for me and are GREATLY appreciated) I come up with Nichicon cap parts numbers in stock at mouser.com. A LOT of my recent posts (1050,1080,1250 etc) in threads can supply examples of this.

you will notice that to post an excel spreadsheet, zipping it is the way to get the board software to accept the post.

read these, especially:
in this thread :http://www.audiokarma.org/forums/showthread.php?t=322650
this post:http://www.audiokarma.org/forums/showpost.php?p=4042555&postcount=15


***************************************

now here is an accumulated file that was probably posted somewhere else already, it is mainy EchoWar's comments then some of my own:

Normally, you'd be correct to properly troubleshoot the problem first, but the Spec 2 runs the VAS stage so hard that those transistors are almost always fried from years of use. When I rebuild a Spec 2, every transistor on the driver board gets replaced.

Q1 to assure good offset,
Q4, Q5, Q6, and Q12 with new MJE15032G's,
Q7 & Q13 with new MJE15033G,
Q8, Q9, Q10 & Q11 with Fairchild equivalents
(especially if the amp has ever been blown and had shorted outputs),
and Q2 & Q3 just because everything else was done
(I use Fairchild KSA992 here). D2 is a 34V 1W zener, and I use a series'd
pair of 17V 500mW zeners to replace, since a 34V 1W zener is an oddball,
and lastly I replace the bias interrupt relay as outlined here.

When the transistors in the VAS stage (Q4~Q7) go wacky, it's not unusual to see the power meter going silly buggers. But failures of one or more of the meter driver transistors (Q1~Q8 on the meter amp assy) are also common.
I simply replace them all with new Fairchild KSC945 and KSA733,
same transistors used in the V/I limiter on the amp board.
__________________
mtf
__________________

Ok, just want to get a quick warning about the ksa733's and ksc945's
(Q8 - Q11 & meters) in here for the record:

The ksa733 has an ebc pinout
the ksa733C has a center collector pinout: ecb

mouser.com

512-KSA733LBU to-92 eBc 50v .15a .25w 180mhz 40-700hfe $0.05 ea
512-KSC945LBU to-92 eBc 50v .15a .25w 300mhz 40-700hfe $0.05 ea
....
512-KSA733CLTA to-92 eCb 50v .15a .25w 180mhz 40-700hfe $0.05 ea
512-KSC945CLTA to-92 eCb 50v .15a .25w 300mhz 40-700hfe $0.05 ea

bu = bulk
ta = ammo strip

and the mje15033 has been out, with a 4/19 (703 quan) ship date at mouser.

been waitin for that one to get back in stock.

863-MJE15033G pnp to-220 bce 250v 8a 50w 30mhz 70hfe $0.87
863-MJE15032G npn to-220 bce 250v 8a 50w 30mhz 70hfe $0.87

512-KSA992FBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.05 ea
512-KSC1845UBU (ln)to-92 ecb 120v .05a .5w 100mhz 150-800hfe $0.05 ea

512-1N5247B Fairchild 17 V, 0.5W Zener


and just for grins, outputs:
........534-4662 to-3 mica insulators $0.16 each.................
863-MJ21193G pnp to-3 250v 16A 250W 4mhz 8-75hfe $3.83
863-MJ21194G npn to-3 250v 16A 250W 4mhz 8-75hfe $3.83


here's a quote you may find, BUT there are obsoleted numbers on it, which have been corrected

Quote:
Originally Posted by donberry View Post
For what it is worth.
Was thinking it might be nice to have all of these in one place.
Here is a list of all of the replacement transistors.
All I did was go thru old posts and copy those down -
mostly compliments of Markthefixer and echowars.
I was not 100% sure about Q12 on the meter board.
Amp Board
Q1 – 2SA798
Q2 - 2SA872 - 512-KSA992FBU
Q3 - 2SA872 - 512-KSA992FBU
Q4 – 2SD610A - MJE15032G
Q5 - 2SD610A - MJE15032G
Q6 - 2SD610A - MJE15032G
Q7 - 2SB630A = MJE15033G
Q8 - 2SA733 - 512-KSA733CLTA
Q9 2SC945 - 512-KSC945CLTA
Q10 - 2SC945 - 512-KSC945CLTA
Q11 - 2SA733 - 512-KSA733CLTA
Q12 - 2SD610A - MJE15032G
Q13 - 2SB630A = MJE15033G

Meter Board
Q1 -2SC1312 - 512-KSC1845EBU
Q2 - 2SC1312 - 512-KSC1845EBU
Q3 – 2SA725 - 512-KSA992FBU
Q4 - 2SA725 - 512-KSA992FBU
Q5 - 2SA725 - 512-KSA992FBU
Q6 - 2SA725 - 512-KSA992FBU
Q7 - 2SC1312 - 512-KSC1845EBU
Q8 - 2SC1312 - 512-KSC1845EBU
Q9 - 2SC1312 - 512-KSC1845EBU
Q10 - 2SC1312 - 512-KSC1845EBU
Q11 - 2SA733 - 512-KSA733CLTA
Q12 – 2SC1384 - 512-KSC2682YSTU to-126 ecb 180v .1a 1.2/8w 200mhz 100-320hfe $0.31 ea obsoleted!!!, current dump for turnoff
Q12new - 2sc1384 - 512-KSC2383YBU to-92L ecb 160v 1a .9w 50mhz 160-320hfe $0.17
Q13 - 2SC945 - 512-KSC945CLTA
Q14 - 2SC1384 - 512-KSC2682YSTU to-126 ecb 180v .1a 1.2/8w 200mhz 100-320hfe $0.31 ea obsoleted!!!, relay drive
Q14new - 2sc1384 - 512-KSC2383YBU to-92L ecb 160v 1a .9w 50mhz 160-320hfe $0.17
Q14mtf - 512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40
Q15 - 2SC1384 - 512-KSC2682YSTU to-126 ecb 180v .1a 1.2/8w 200mhz 100-320hfe $0.31 ea obsoleted!!!, lamp drive
Q15new - 2sc1384 - 512-KSC2383YBU to-92L ecb 160v 1a .9w 50mhz 160-320hfe $0.17
Q15mtf - 512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40
Q16 - 2SD313 - 512-KSC2073TU
Q17 - 2SB507 - 512-KSA940TU_Q

RL-1 Reed Relay - Hamlin HE3300 Series 24V SPST relay. Part #HE129-ND(amp board) (this is a digikey number)

(notice no capacitors, I await your posting of an excel spreadsheet, as a ZIP file)

********************* and yet another ****************
 
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Amplifier Boards completed

I finished the boards today and have been double checking my work a few times over. Last night I reviewed several threads from 2008 where EW discussed the trimmer adjustments and setting them. One was; a member had a DC balance which would not zero. EW mentioned "DC offset tweaking on a breadboard". Is this something I might need to deal with? I guess I'll find out soon enough! The matched pair (KSA992's) are gain matched to the tee.

You'll notice I left the original current VR's installed. I mapped them and then checked for sweep. No issues, so I'm going to leave them. I did order a set of 100 ohm Bourn's trimmers but I want to move forward on the set and may change them out later. Now, the set was operational before I started on the Amp boards. I haven't messed with the set other than the amps. Tonight or better, tomorrow, install and set them up.

The large filter caps are on their way.

EDIT 05-25-2015:
This board is correct and is functional, meeting all Pioneer SM spec's.
This is an edited image so I won't confuse any with the wrong RL5 (Dead bug connections) of the previous (Removed) image. It also shows the single Q1, 2SA798 transistor installed. I ended up using a matched pair of the KSA992's instead. See below posts for a better explanation. Also installed are a single turn Bourns trimmers for the current limiting relay. MTF saw the originals and made a comment in the next post. :yes:

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Yes, :tears:
I do have 652-3329W-1-101LF trimmers ordered along with a few other relays and such. Won't be here until Tuesday. I did check them and they are fine, not what I wanted to do, set it up twice, but I would like to make sure the Boards are good so I can move to the PS or meter board.
 
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Fry's has multiturn trimmers that look like repackaged bourns (blue with the same model number) if you can't wait till Tuesday. They are probably better than the old stock ones and you can always replace them when you get your order.
 
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