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Pioneer SX-3800

AM/FM Stereo Receiver (1980-81)

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Pioneer SX-3800


The Pioneer SX-3800 is an AM/FM stereo receiver incorporating a non-switching amplifier and digital, quartz-servo locked tuning.


Tuning range: FM, MW

Power output: 60 watts per channel into 8Ω (stereo)

Frequency response: 7Hz to 80kHz

Total harmonic distortion: 0.005%

Damping factor: 50

Input sensitivity: 2.5mV (MM), 150mV (line)

Signal to noise ratio: 82dB (MM), 110dB (line)

Output: 150mV (line)

Semiconductors: 17 x IC, 6 x FET, 71 x transistors, 58 x diodes

Dimensions: 506 x 164 x 434mm

Weight: 16.2kg

Accessories: FM T-type antenna

Year: 1980


schematics   English -

service manual   English -

service additional   English -

instruction/owners manual   English - pwsheehan

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Reviewed Dec 21st, 2014 by arronmason619

Pioneer SX-3800 stereo reciever '80-'81.
Has fantastic sounding FM tuner and awesome
non-switching amplifier for great sound and no
audible distortion. The amp section has lots of
power for almost any speaker pair.



pioneer sx 3800 no sound

hello. i have a receiver where everything works except no sound. when volume is turned up all the way, i can barely hear music when my ear is up to the speaker. is it some thing to do with speakers connection and is it an easy fix or novice or should a pro handle this. i would like to keep cost low. i have tried other wires and other speakers already.

Pioneer sx3800

My reciever was working fine and then the sound stopped. A display says "W 8ohms" on the front. I understand from the manual that a relay was broken but it doesn't say how to repair it. Does anyone have any ideas? There are no speaker fuses.
thanks in advance.

Speaker protection...

Sounds like the speaker protection relay kicked out. I've worked on many SX-series Pioneers. First, check both ends of the speaker connections, the smallest stray strand of wire crossing the two leads will trip the relay. Next, Disconnect the speakers completely, then in a quiet room, turn on the power, within five seconds, you should hear the distinct click of the relay closing on. If the relay clicks, try connecting the speakers again, if the relay trips again, its shorted speaker leads or a shorted speaker voice coil. Try a different set of speaker leads then different speakers. If the relay appears to be working correctly but still no sound, then the relay contact points may have become oxidized. Using the finest grit emery paper you can get (400 or finer), remove the relay cover and carefully slide the (folded) paper between the open contacts, since you are working with the power off, these should be open. Just a light swipe should do the trick. This is a temporary fix, once the contacts start to corrode, they will continue to haunt you until you replace that relay, fortunately it is a very common relay, with a twelve volt coil and either two or four sets of contacts, depending in the model. Count the number of wires going to it Six wires means two sets, 10 wires means four sets. Copy any numbers you find on the relay and do an internet search. Newark, Digi-Key, Allied Electronics, will all have replacements for around $10, the trick will be getting the correct size for a drop-in replacement.
If you have headphones, see if the music comes through the phones with the speakers switched off. If you hear distorted music or a loud hum over the music, chances are the output transistors have shorted. Fear not, they are also easily replaced. Looking at the big black fins you'll see chrome round discs about the size of a quarter, but thicker, held by two screws. Write down those the bold numbers. American transistors use the 2NXXX numbering system, the Japanese system uses 2Sxxxx. Yours will start with one letter followed by three or four numbers, so an A2345 translates to 2SA2345. They will be in complementary pairs, if you don't know which pair is bad, it you will have to either buy a whole set, or gamble you pick the correct pair ,on the first shot. i.e. if you pick a bad one and a good one, the remaining bad one will takeout the good one you just put in. They will run about $12 each. Or if you are handy with an ohm meter. mark the locations of all the transistors, better yet, only pull one at a time. Measure pin to case and pin to pin, in both directions, a low reading in one direction, a high reading in the other, the collector is typically the case. if you get readings under 10 ohms in both directions pin to pin or pin to case, that's the bad one.

pioner sx 3800

Well i eventually found the time to unplug the reciever, disconnect the speakers, leave it for five minutes etc but the sound didn't come on and the sign on the display remains the same.
I took the top of but do not know what the relay cover looks like or where to find it!! I check all the fuses etc and they all seem fine.
Where are the relays and what do they look like?
Any advice is appreciated.

pioneer sx 3800

Thanks so much for all this. i will read it and see what i can do. Much obliged for your quick response.

Poineer Reciver SX 3800

I was try to replace my lamps and I have broke my Balance control while I try to remove the front panel.

If any one out there could help me find one to replace it.
I Thank You.

Ignacio Perez

Search: vintage hifi

As most stereos have digital controls, you are almost certainly looking for old stock out of someone's hoard. I have such a control from a SX650. it may or may not fit your unit. The real challenge here is disassembling and reassembling the entire front panel (as you have already discovered). Normally I would give you instructions on how to match-up a replacement, one that I might actually have, but I'm not sure you are the tech to undertake this surgery. Almost anywhere you look in this country there are competent techs that work for reasonable rates. Do an internet search for : vintage audio repair, or just stereo repair, tell them what you situation is, a repair like that will be very straight forward, meaning they should be able to quote you a price right over the phone.

This website is not affiliated with or sponsored by Pioneer. To purchase SX-3800 spares or accessories, please contact the company via their website or visit an authorised retailer.