Home |
Search |
Today's Posts |
![]() |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Picked this up a few months back and just hauled it out. The units
power up, and lights come on but the cassette deck stubbornly remains dead. This is a 'pseudo-separates' affair, where each box is connected by means of a flat ribbon cable. The main trafo. is in the amp which then feeds a 'sound processor'/input selector box, from whence the dvd and cassette decks are fed. The dvd, which is downstream from the cassette, powers up fine. I'm assuming they use the same power rail, so will concentrate on the cassette unit first. Going to take some measurements on the cassette pcb, but I'd like the service data to speed things up, as this is quite a complex unit and it would save me the hassle of having to unscrew and open all the boxes to trace the basic voltage lines. Anyone suggest a source for a schematic? Tried eserviceinfo to no avail.... cheers, B |
#2
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Jul 27, 5:48*pm, b wrote:
Picked this up a few months back and just hauled it out. The units power up, and lights come on but the cassette deck stubbornly remains dead. Also forgot to mention: no audio through speakers, and through headphones nothing either -well, I get a low hiss (vol. at full) when in tuner mode, despite the search mode working and stations appearing as 'tuned' in the display.... -B |
#3
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Tue, 27 Jul 2010 09:35:17 -0700, b wrote:
On Jul 27, 5:48Â*pm, b wrote: Picked this up a few months back and just hauled it out. The units power up, and lights come on but the cassette deck stubbornly remains dead. Also forgot to mention: no audio through speakers, and through headphones nothing either -well, I get a low hiss (vol. at full) when in tuner mode, despite the search mode working and stations appearing as 'tuned' in the display.... -B My educated and experienced guess is a missing voltage. |
#4
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() "b" wrote in message ... Picked this up a few months back and just hauled it out. The units power up, and lights come on but the cassette deck stubbornly remains dead. This is a 'pseudo-separates' affair, where each box is connected by means of a flat ribbon cable. The main trafo. is in the amp which then feeds a 'sound processor'/input selector box, from whence the dvd and cassette decks are fed. The dvd, which is downstream from the cassette, powers up fine. I'm assuming they use the same power rail, so will concentrate on the cassette unit first. Going to take some measurements on the cassette pcb, but I'd like the service data to speed things up, as this is quite a complex unit and it would save me the hassle of having to unscrew and open all the boxes to trace the basic voltage lines. Anyone suggest a source for a schematic? Tried eserviceinfo to no avail.... cheers, B I've sent you a set of schematics direct off-group. Let me know that you get them ok Arfa |
#5
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Jul 28, 3:10*am, "Arfa Daily" wrote:
"b" wrote in message ... Picked this up a few months back and just hauled it out. The units power up, and lights come on but the cassette deck stubbornly remains dead. This is a 'pseudo-separates' affair, where each box is connected by means of a flat ribbon cable. The main trafo. is in the amp which then feeds a 'sound processor'/input selector box, from whence the dvd and cassette decks are fed. The dvd, which is downstream from the cassette, powers up fine. I'm assuming they use the same power rail, so will concentrate on the cassette unit first. Going to take some measurements on the cassette pcb, but I'd like the service data to speed things up, as this is quite a complex unit and it would save me the hassle of having to unscrew and open all the boxes to trace the basic voltage lines. Anyone suggest a source for a schematic? Tried eserviceinfo to no avail.... cheers, B I've sent you a set of schematics direct off-group. Let me know that you get them ok Arfa Quick update. Took a few measurements - all 3 entry safety resistors in the cassette main pcb 'psu' are fine with the correct voltages present. Checked Q604, which drops the 10v to 5v and that has 5v on its emittter. This 5v is also present on pin 5 of main pcb connector 901 which goes to the LED/button panel. Checked Q602 the 9.6v regulator. Voltage present and correct there too. hmmm... could this be something amiss on the button /LED panel? Will do this next. As an aside, whilst I had the thing on, I noticed there is a sub pcb in the amp module with 3x B1548 power transistors mounted on a small heatsink - getting red hot, not a good sign. may or may not be related. -B |
#6
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() "b" wrote in message ... On Jul 28, 3:10 am, "Arfa Daily" wrote: "b" wrote in message ... Picked this up a few months back and just hauled it out. The units power up, and lights come on but the cassette deck stubbornly remains dead. This is a 'pseudo-separates' affair, where each box is connected by means of a flat ribbon cable. The main trafo. is in the amp which then feeds a 'sound processor'/input selector box, from whence the dvd and cassette decks are fed. The dvd, which is downstream from the cassette, powers up fine. I'm assuming they use the same power rail, so will concentrate on the cassette unit first. Going to take some measurements on the cassette pcb, but I'd like the service data to speed things up, as this is quite a complex unit and it would save me the hassle of having to unscrew and open all the boxes to trace the basic voltage lines. Anyone suggest a source for a schematic? Tried eserviceinfo to no avail.... cheers, B I've sent you a set of schematics direct off-group. Let me know that you get them ok Arfa Quick update. Took a few measurements - all 3 entry safety resistors in the cassette main pcb 'psu' are fine with the correct voltages present. Checked Q604, which drops the 10v to 5v and that has 5v on its emittter. This 5v is also present on pin 5 of main pcb connector 901 which goes to the LED/button panel. Checked Q602 the 9.6v regulator. Voltage present and correct there too. hmmm... could this be something amiss on the button /LED panel? Will do this next. As an aside, whilst I had the thing on, I noticed there is a sub pcb in the amp module with 3x B1548 power transistors mounted on a small heatsink - getting red hot, not a good sign. may or may not be related. -B These units are known for bad joints on any heatsink-attached transistors. Arfa |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Technics RS-TR255 Cassette Decks | Electronics Repair | |||
Technics component stereo system from 1993 | Electronics Repair | |||
Technics RS-TR555 Double Cassette Deck Part 2 | Electronics Repair | |||
Technics RS-TR555 Double Cassette Deck | Electronics Repair | |||
Technics RS-TR373 cassette deck problem | Electronics Repair |