Pioneer Pro Amp With No Model Number, Anyone Ever See One Of These ?

One wierd thing about this one also is that from the voltage readings on th e good (in fact both) channels, it uses bipolars but with the base or emitt er in the middle. You can see the construction there, they mirrored it but flipped one side upside down. However input and all that are on one side. W hy the hell didn't they just mirror it the other way ?

Anyway, I doubt it needs outputs from the readings, but it seems the output s have the base (or maybe the emitter) in the middle, not the collector. An d they are all the same polarity. I can't see the numbers and I am not taki ng that part of it apart unless necessary. But on one side they got like -1

00V on two pins and 0 on the other. On the other ones they got +100V on one pin but 0 on the other two. The difference is that the other is on the end instead of the middle.

Anyway, here are some pictures (higher res available on request) :

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It may be a little hard to see in those pictures but it is a two sided boar d which makes any reverse engineeering alot harder. If I could just find a print it would help.

I got no output on the right channel, or B or whatever. It is not in protec tion. The readings look the same as the other channel.

Any idea what it is ? Any help is appreciated. If not I gotta tear into it blind because you really can't get to much. Anything, even the model number might help. I doubt any idiot ripped the numbers off because it was hot be cause the serial number is still there.

Reply to
jurb6006
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Well, the sticker says that it's made by Pioneer: but is sure doesn't look like anything made by Pioneer. It also says made in 2004 but looks older. I also don't recall anything by Pioneer with a fan (although I may have missed something).

I did some image searching, but couldn't find anything by Pioneer that looked even close:

My guess(tm) is that it's either a counterfeit, or someone just stuck the Pioneer name on some other device in order to enhance its resale value.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

the good (in fact both) channels, it uses bipolars but with the base or emi tter in the middle. You can see the construction there, they mirrored it bu t flipped one side upside down. However input and all that are on one side. Why the hell didn't they just mirror it the other way ?

uts have the base (or maybe the emitter) in the middle, not the collector. And they are all the same polarity. I can't see the numbers and I am not ta king that part of it apart unless necessary. But on one side they got like

-100V on two pins and 0 on the other. On the other ones they got +100V on o ne pin but 0 on the other two. The difference is that the other is on the e nd instead of the middle.

ard which makes any reverse engineeering alot harder. If I could just find a print it would help.

ection. The readings look the same as the other channel.

t blind because you really can't get to much. Anything, even the model numb er might help. I doubt any idiot ripped the numbers off because it was hot because the serial number is still there.

** That is a USA made amplifier - not Pioneer.

FYI: Asian electronic gear has metric thread bolts and I but that POS has Yankee ones.

If the middle pin on a large flyt pak is not a collector, then the devices are lateral Mosfets.

... Phil

Reply to
Phil Allison

How could you tell that from the picures ? those aren't even the hi res one s. (not that they're all that good)

s are >lateral Mosfets."

Never heard of them befroe but oww tht I had a look around the net I se tha t possible. they said the bias rquirements are similar to bipolar, I assume that means voltage ? I mean, if you have to drive it with current then you o are back where you started. Regardless I did nmeasure about the same volt age on two adjacent pins and a far awy voltage on the other end in all case s. I found the coil whee it comes out and it has no offsaet. The relays are separate fro each channels and I hear them both click in. There is no heav y drain. ust a surge when it comes on. It is pretty hard for it to be anyth oing but someting in the signal path rather than the power amps themselves.

I might just have to figure it out myself. But now I am even more adamant a bout not breaking the seals on those outputs. If I have to pull that channe l I will get them but other than that f*ck it. The other channel I am leavi ng alone of course.

I am almost intereted in seeng the actual curves n shit on these lateral FE Ts. I doubt I'll ever use one purposely in a circuit, but it is nice to kno w. Like when you read a Tektronix manual and it explains all about tunnel d iodes and unijunction transistors. Actually worht the read but, once.

Reply to
jurb6006

I also don't recall anything by Pioneer

I guess you missed the joy of the low end Pioneer receivers that had what w e call the "music to smoke converter" module. It was a Borg type cube that had all the outputs plus the two driver boards stuffed into a chimney with an exhaust fan that would blow the smoke from the inevitable failure quick ly out the back.

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Reply to
John-Del

This unit looks to me like an older Crest amp. They usually have markings on the front, but this one may have either worn off or been removed. Crest systems don't usually have the name on the back either.

The Pioneer name on the back looks like someone added it on.

Dan

Reply to
dansabrservices

Looks like a legit serial number sticker but I need more pics of the unit itself.

Inside pics would help too.

Mark Z.

Reply to
Mark Zacharias

Disclaimer: I don't do this for a living.

I would look at those normal/bridging and stereo/parallel-mono switches, as well as the level pots for the inputs. If there is an op-amp (to bring a low input up) or maybe a resistor divider (to bring a high input down) on that input board, check that too. A problem on the input board might result in nothing getting to the power stages.

Matt Roberds

Reply to
mroberds

** ROTFL !!

I can tell it's a USA made from the pics - lotsa clues that you see only in US made amps.

CONFIRMATION can be had by looking at the threads on the bolts, US threads = US made.

... Phil

Reply to
Phil Allison

I serviced high-power amps part-time and You do have to understand bridging. Judging from the "DUST", those switches likely need a cleaning.

With no input and no load measure the DC voltage from ground to + spk and - spk and +spk to ground and -spk to ground L&R in bridge and non-bridge mode.

Particularly you get exactly zero between spk- and spk+ in normal mode, I'd look at the output relay. You should at least see a few mv unless the amp is capacitive coupled.

You have DIN and phone plug inputs so concentrate on the phone plugs.

Relays could exist in the input circuit as well. Without a minimum current or the right relays, the contacts could be oxidized.

One way to bridge is to invert one signal and to take the output from the + spk terminals w/o using ground.

So what I am suggesting is oxidation of relay contacts on the input or output or something between the ears (user error).

Reply to
Ron D.

we >call the "music to smoke converter" module. It was a Borg type cube"

Oh no, I just didn't do audio at th time except for a few high end us-nius came in. I was doing rear projection mostly, where the money was. But I saw them. they gave up on fixing them and were ordering them somnewehere and d ropping them in. the parts guy at that place was FANTASTIC. I would say "Se e if you can get htis, if not I'll work on it sone more". He would have in two days. I have no idea how he does it. He is doing oit for their shop up here and oin FLorida where they are about to semi retire. they already have a shop and once the shop up here is sold he goes down ther and works with his partner down there and thety forget about all this snow n shit. At leas t that's the plane. Problem is the shop is down to fifty grand and still no t selling. they probably shouldv'e sold out about 15 years ago back ewhen I workded for them.

The7 f***ed up alot of audio. They are simply NOT an audio shop. they could be wit me but I was no longer willing to work full time, and thenm part ti mee, and then traded jobs with a guy who lived nearer there and we both sav ed 20 miles on our commute. And it worked out I guess. None of these Tv pla ces really evr wantd to do audio.

But I wish I could use their parts guy. Today it wouldn't matter as much fo r a lot of reasons, but his ability to gt parts really made the difference and we watched tho competition go under again and again.

but yes, I am aware of Pioneer's back eye which send them to the bottom end . you know at one time they buillt what is known as the SX-1980. OPne of th e best receivers ever. and now I wouldn't hit a dog in the ass with the bes t of their best today. Oh yeah, I know it is not sold at Walmart, but if th ey'll put that name on that, they'll put it on anything. Fukum, they are de ad. Stick a fork in them, they are done.

Reply to
jurb6006

I had a closer look at that. What a lame ass attempt.

Reply to
jurb6006

I got what I could. I have put it down for reasons I will explain in another post very soon tonight. If I HAVE to fix it I will be back, with a $150 to $250 estimate approved. the amp might not be worth that in this market so I doubt that is happening.

Reply to
jurb6006

I have been at this a whioe. Yes I checked and the input is getting all the way to the amp board itself, which contains all pretection circuitry. I wo uld have switched amp boards except for what I found which is coming in a " supra" post. (not a toppost but closer to it)

Reply to
jurb6006

OK so it was just the looks of the thing. I guess I agree but I am experienced on US, Japanese and Chines/Korean/Viet/Malasian stuff. I know there is alot else out there.

Reply to
jurb6006

Understood but they don't. I will be back with the results in a few minutes once I get through all the individual issues everyone has brought up.

Reply to
jurb6006

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