Pioneer SPEC 2 restoration help

Greetings from the UK, all. One day left before I return. Happened to stop in a industrial fastener shop and inquired about small metric screws. Gentleman happened to have 70 3x8mm black phillips pan head screws that matched the cover screws for the SPEC 2. Also picked up some black 4x8mm panhead screws and an assortment of metric SS screws for the handles just in case I couldn't find black ones anywhere. Made my day. Couldn't find the STV-4H, though. :tears: Still, I'm pretty happy about the screws. :banana::banana::banana:

Cheers, all.
 
Parts update:

I ordered 3 STV3H-Y's per EchoWars part number thru the Partstore on Thursday and the Partstore says they shipped on Saturday. I'm amazed. :banana::banana: I'll be even more amazed if/when they really show up at my door. :yes:

All I need now are the two STV4H's (I have a lead on those), an audio generator, and an oscilloscope.

Onward we march.
 
Slipstream55,

I will be intrested to see if you can track down some STV-4Hs. I had the unfortunate luck of breaking one during my repair. I tried the EchoWars fix over the weekend with a 2V zener but it does not quite work. My next attemp will be to use a STV-3H with an odd diode in seris to make up a substitute STV-4H. I hve two on order from Partstore.

I use an audio CD with tracks recorded of various sine waves for a signal generator. I loop the 1000Hz track and it works OK for setting the power output and tracking the signal through the circuit. Its not going to be as clean as a signal generator but it gets the job done. I think I bought the CD from Part Express or MCM Electronics. I've had it for quite some time.

Ray
 
Ramundo said:
Slipstream55,

I will be intrested to see if you can track down some STV-4Hs. I had the unfortunate luck of breaking one during my repair. I tried the EchoWars fix over the weekend with a 2V zener but it does not quite work. My next attemp will be to use a STV-3H with an odd diode in seris to make up a substitute STV-4H. I hve two on order from Partstore.

I use an audio CD with tracks recorded of various sine waves for a signal generator. I loop the 1000Hz track and it works OK for setting the power output and tracking the signal through the circuit. Its not going to be as clean as a signal generator but it gets the job done. I think I bought the CD from Part Express or MCM Electronics. I've had it for quite some time.

Ray
Click to expand...

Ray,

Don't want to get this thread off track but I also was trying to figure out what I could use for a tone generator for one of my repairs. I ened up using an application on my laptop that I found by Googling "tone generator application". There are a number of them out there. I ended up using the one from NCH and it works great!
 
xlbee...I wouldn't consider your post off track (off subject?, whatever) as it is useful information and needed for the driver board alignment in the event I can't find an Audio Generator. Thanks for your input. :thmbsp:

Cheers.

(my trip to the UK has affected me afterall) :D
 
EchoWars:

Does the SX-850 use the STV4H. I couldn't find a service manual to verify this but the schematic indicates that it might. Thx.
 
slipstream55 said:
EchoWars:

Does the SX-850 use the STV4H. I couldn't find a service manual to verify this but the schematic indicates that it might. Thx.
Click to expand...

Yes it does, I'm working on a database of all active devices in some of the pioneer receivers.
 
I have another question regarding my SPEC-2 restoration project for anyone who can provide an answer. If there is anyone still around who worked for Pioneer (Engineering/development) back in the 70s or 80s, this should be right up your alley.

What type of paint did Pioneer use on their case covers for the SPEC components, RT-7xx and RT-9xx series R2Rs, and other components? It is a black, textured paint that may have been baked on.

I am looking at two products for the oxidation/rust removal of the metal parts (covers, screws, etc.) prior to painting. The first one, believe it or not, is a mixture of water and molasses (ratio of 9 water to 1 molasses). The second one is a product called "Safest Rust Remover.Com". They both use a chelation process to remove rust without affecting surrounding paint (no acid). I was looking at Evapo-Rust but this may not be as thorough a remover as "Safest..." is.

Anyway, I'm really curious about the paint question. I located 2 STV-4H diode packs. We'll see if they come in. Am still waiting for the STV-3H diode packs. My card was charged and I was told they shipped but it's been over a week now and no parts yet.

I'll post to this thread if I get my parts in. Thanks for all the help and input so far.
 
Missing STV-3H(Y)'s from The PartStore aren't missing anymore. FedEx tracking showed they were delivered at the door on 4/16, just 4 days after I ordered them. After I got back from my trip to Virginia (4/23) I looked around the front door area and found a padded envelope under the bushes by the door. The wind must have blown it there or the FedEx guy thought it would be safer under the bushes. I am surprised (1) these weren't in a box because of how fragile they are and (2) that FedEx left them at the door without requiring a body to deliver to. FedEx never does this at my house for anything I have ever gotten from them. There always had to be someone home to receive anything. Anyway, my 3 STV-3H parts are here safe and sound. Waiting for the STV-4H parts to come in now. Stay tuned.
 
Slipstream55,

Where did you find the STV-4Hs?

I made up an STV-4H with 4, 1N914 diodes potted in thermally conductive epoxy. The bias adjust was more sensitive on this channel but the amp is now alive and I'm back in audio nirvana. I do have some STV-3Hs on order too that I was going to use with one additional 1N914 diode to make the STV-4H. Partstore has my STV-3Hs on back order so I tried the make my own STV-4H approach which seems to be working out. If I can find an STV-4H I will swap it in later.

Good luck with your rebuild. I only had one bad channel to contend with and just the 30 years of dust inside. Your Spec 2 seems like its going to require much more TLC.

Ray
 
Thanks for the sentiments, Ray, but...TLC my as$. It's going to need a major dose of Extreme Makeover (Home Edition) or should I say SPEC Edition before its ready to play again. I got the STV-4H's from a parts receiver I recently purchased while in Virginia. At least I hope they're in there. I haven't received the receiver yet and won't know I actually have them until I go back to Virginia on Monday and see they are there.
 
It is Wednesday evening and I finally received the SX-850 parts chassis. :banana: The 2 STV-4H diode packs were included :banana::banana: and have been successfully removed :banana::banana::banana:. Also extracted quite a bit of common screws and hardware from the chassis that can be used on the SPEC-2 restoration project. I am much happier now :huge:. So here I sit, screw driver in hand, Bass Pale Ales at my side :beer:, and 3 hours of free time I will spend stripping this old SX-850 chassis. Fun. :thmbsp:
 
I'm a little embarrassed to be asking this but...how do I verify an STV-4H diode pack is good? I tried the diode check function on my Fluke 8024B multimeter. Results on both diode packs was "open" both ways. I expected to see an open one way, short the other way. I'm guessing that this needs to be done with an analog meter. I'm having a hard time beleiving both packs are bad. Help, anyone? Thanks.

BTW, the STV-4H leads were extremely tarnished. I used MAAS metal polishing creme to clean them up (carefully, of course). It works great. I use this on tarnished RCA jacks on vintage equipment with great results. MAAS can be found at ACE Hardware.
 
Some meters simply don't have enough forward voltage on the diode test to check a 4-junction device. My Fluke 179 can't do it, but my Fluke 183 can.

Got a bench power supply? 5V + STV-4H diode + 1K resistor = diode confirmation. Hell, even a 9V battery. Simply measure the voltage across the diode...about 2 to 2.2V one way (forward biased), and you'll read the total supply voltage when the diode is reversed.

Don't forget the resistor, else the diode is :smshot:
 
I've been away from my Pioneer projects for awhile. Now I'm back on them (for awhile, anyway). Question for EchoWars...regarding the test of the STV-4H diodes. I like the 9volt battery check as I don't have access to a power supply at the moment. Does the 1K resistor go in series with the diode?

(Pos. supply + 1K + diode + Neg supply)

Thanks.
 
Hi, all. I'm back on my SPEC-2 project for awhile. Believe it or not, I've been too busy with yard work and home projects playing catch-up from work related travel. On top of that, we've been car shopping for my teen daughter on the week-ends. I absolutely hate car shopping and car salesmen now (hope none of you AKers sell cars for a living) and have the gray hairs and high blood pressure to prove it.

Anyway, the local auto paint retaler didn't pan out for the spatter finish paint as I was hoping it would. I am now down to 3 options: wrinkle finish, black satin hammered finish, or an attempt at a spatter finish that is not guaranteed to be spatter finish when I'm done. None of the above will have the SPEC-2 looking out of box original but it does need a paint job. Any recommendations?

On an aside. The molassas bath did remove the rust as advertised but does nothing for anything under the paint or the white oxidation spots on top of the paint. It smells nice now, though.
 
Been on VaCa, my friend (and I still am), but yes...unless you want to destroy that diode, the resistor is your series current-limiting device. Not much sense in connecting it any other way. ;)
 
I am getting ready to have the SPEC-2 heatsinks anodized. I was hit with the following question when I spoke with the customer service guy at the company doing the anodizing..."Do you want Type I or Type II anodizing?" Well, I know what the differences are and the guy recommended Type II. If anyone has done this before (EchoWars?), which one did you choose and why? I'm hearing $75 and up to have this done.

Oh well. Everyone has said this restoration wasn't going to be cheap.

Side note: I just scored a Tektronix 475A for the SPEC-2 Driver board alignment. I'll post the short story on the scope in DIY this evening. I have some questions regarding getting the scope ready for use.

Thanks all, for your time and ears.
 
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