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QRX 9001 Diagnosis (Best Guess)

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wiztom

Member
Joined
May 8, 2019
Messages
11
Location
Dallas, Texas
Picked up a QRX-9001 which appears in good condition, but has been setting a while.
Powered it up and the left rear channel and meter are not working. When listening through the earphones to an FM station in stereo mode it sounds OK.
Rear channels in quad mode is silent on the right and a loud hum on the left.
Following the many discussions about the receiver I took the following measurements:
Driver boards: 150 ohm and 180 ohm fusible resistors vary out of speck by around 20 to 40 ohms.
F2639 board top to bottom is 39 V, 25.6 V 23.6 V 10.8 V
Readings at earphone plugs: Front: 198 / 191 Rear 187 / 55.3 V ? (had to range out to get a reading).
No speaker output so I am going to assume its in protection mode. Visually saw nothing that looked fried.
I am assuming that there is some type of short to ground on the rear left channel?

I am not going to repair it, as I already have a working one. I will just put it up for auction on E-Bay but would like some idea of what a buyer may be looking at as far as repair.

Thanks
 

Soundfield

701 Club - QQ All-Star
Joined
Dec 29, 2011
Messages
744
Location
Essex, UK
Readings at earphone plugs: Front: 198 / 191 Rear 187 / 55.3 V ? (had to range out to get a reading).

I will just put it up for auction on E-Bay

Thanks
If you've really got 198V on the headphone jacks you should warn any customer it is potentially lethal!
 
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bigbillquad

1K Club - QQ Shooting Star
QQ Supporter
Joined
Dec 6, 2010
Messages
1,318
Location
New Zealand . Waitakere
Picked up a QRX-9001 which appears in good condition, but has been setting a while.
Powered it up and the left rear channel and meter are not working. When listening through the earphones to an FM station in stereo mode it sounds OK.
Rear channels in quad mode is silent on the right and a loud hum on the left.
Following the many discussions about the receiver I took the following measurements:
Driver boards: 150 ohm and 180 ohm fusible resistors vary out of speck by around 20 to 40 ohms.
F2639 board top to bottom is 39 V, 25.6 V 23.6 V 10.8 V
Readings at earphone plugs: Front: 198 / 191 Rear 187 / 55.3 V ? (had to range out to get a reading).
No speaker output so I am going to assume its in protection mode. Visually saw nothing that looked fried.
I am assuming that there is some type of short to ground on the rear left channel?

I am not going to repair it, as I already have a working one. I will just put it up for auction on E-Bay but would like some idea of what a buyer may be looking at as far as repair.

Thanks
HI. wiztom

A view years back when I bought a QRX 8001 I sent it to ( https://www.qrxrestore.com/ ) and had it fully restored great work and is still performing today Jim Showker past away not long ago but his son and nephew is carrying on the business go to the there site I am sure they have a brake down of the cost of repairs you can get a idea from..
BBQ...
 
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