ChopperCharles
Well-known Member
I have a Pioneer QX-4000 receiver that was my father's, given to him by his brother (my uncle) back in the 70's. Not a cheap piece of equipment back then.
Sadly, it stopped working in the 90's, and dad put it in the hot, un-conditioned attic.
Well, my father has since passed on, and I'd like to get this thing up and working 100% again.
I found the original problem, the reason it stopped working. It was simply a bad diode on the muting board. However, spending all of that time in the attic has taken its toll. . I've de-oxited everything, and all the switches, buttons, and dials work with no scratchies. But there's still more. The receiver really needs a COMPLETE going through. It has four main problems:
1. FM Tuner needs an alignment. It can barely pick up strong local stations, even with a 57" dipole antenna in my attic. I have another QX that receives better with no antenna than this one does with the dipole attached.
2. FM Muting doesn't work.
3. RIAA circuit has a warble. Turn it up and listen to the hiss, and every now and then the his will change pitch and sound, like someone is whispering nonesense. I'm thinking probably a bad cap.
4. This is the biggie... the rear channels have issues. 2-channel works great. If I switch to "Regular" 4-channel, I get a ton of pops, crackles, and scratchies. Bass drops out and treble is distorted as well. Sounds somewhat like a dirty switch, but it's not (I used $45 worth of DeOxit cleaning those two switches, and touching and slightly rotating the switch has no effect on the noise being made). The noise it makes is REALLY loud, even if the volume level is relatively low. Switching to SQ 4-channel mode instantly brings the bass back and the treble is no longer distorted. However, I'll still get the occasional scratching noise every minute or two. Sometimes it'll be good for an hour, sometimes it scratches constantly. Switch to discreet 4-channel, and it sounds great. No problems at all. So, there's something amiss with the Quad decoder circuitry, I think.
I know how to solder and do very basic diagnostics. If I were to tackle this, I'd replace every electrolytic in the machine and then be really pissed when that didn't fix the problems. So, I'd rather pay someone to figure out what's wrong and repair it correctly. I also don't have the ability to align the tuner. I have neither the knowledge nor the equipment.
I know I'm probably better off just scouring eBay for a working receiver -- and I've actually done that. I have a second QX4000 that works wonderfully.... but it's not the same. I want my late father's QX back up and running 100%. I'm using it in 2 channels now, just in my bedroom, instead of in the listening room where it belongs.
Any idea of someone who can fix it, and how much it will cost? I'm realizing it's probably not going to be anywhere near cheap, and I'm okay with that.
Charles.
Sadly, it stopped working in the 90's, and dad put it in the hot, un-conditioned attic.
Well, my father has since passed on, and I'd like to get this thing up and working 100% again.
I found the original problem, the reason it stopped working. It was simply a bad diode on the muting board. However, spending all of that time in the attic has taken its toll. . I've de-oxited everything, and all the switches, buttons, and dials work with no scratchies. But there's still more. The receiver really needs a COMPLETE going through. It has four main problems:
1. FM Tuner needs an alignment. It can barely pick up strong local stations, even with a 57" dipole antenna in my attic. I have another QX that receives better with no antenna than this one does with the dipole attached.
2. FM Muting doesn't work.
3. RIAA circuit has a warble. Turn it up and listen to the hiss, and every now and then the his will change pitch and sound, like someone is whispering nonesense. I'm thinking probably a bad cap.
4. This is the biggie... the rear channels have issues. 2-channel works great. If I switch to "Regular" 4-channel, I get a ton of pops, crackles, and scratchies. Bass drops out and treble is distorted as well. Sounds somewhat like a dirty switch, but it's not (I used $45 worth of DeOxit cleaning those two switches, and touching and slightly rotating the switch has no effect on the noise being made). The noise it makes is REALLY loud, even if the volume level is relatively low. Switching to SQ 4-channel mode instantly brings the bass back and the treble is no longer distorted. However, I'll still get the occasional scratching noise every minute or two. Sometimes it'll be good for an hour, sometimes it scratches constantly. Switch to discreet 4-channel, and it sounds great. No problems at all. So, there's something amiss with the Quad decoder circuitry, I think.
I know how to solder and do very basic diagnostics. If I were to tackle this, I'd replace every electrolytic in the machine and then be really pissed when that didn't fix the problems. So, I'd rather pay someone to figure out what's wrong and repair it correctly. I also don't have the ability to align the tuner. I have neither the knowledge nor the equipment.
I know I'm probably better off just scouring eBay for a working receiver -- and I've actually done that. I have a second QX4000 that works wonderfully.... but it's not the same. I want my late father's QX back up and running 100%. I'm using it in 2 channels now, just in my bedroom, instead of in the listening room where it belongs.
Any idea of someone who can fix it, and how much it will cost? I'm realizing it's probably not going to be anywhere near cheap, and I'm okay with that.
Charles.
