I've an old 1994 Bose Wave Radio that I replaced the fuse, audio amp and majority of capacitors (all of 'em around the audio amp and equalizer circuitry; but not all around the FM portion). Problem is, when the volume is increased to about 70 (as seen on the display), the radio starts distorting badly. This happens in AM, FM and AUX IN (when using a little 1khz audio signal generator). OK, so this tells me the problem may be in the equalizer circuitry or the amplifier circuitry (or possibly the power supply - but the caps have been replaced). Anyone have any ideas what the problem could be?
Bose wave radio, dead set.
I'm in the process of fixing one for a friend and as couple people were saying, check and/or replace q4. When doing this, be careful with the copper traces underneath as they are tinier than normal, (as I found out the hard way). However one might need to find a reasonable substitute if all else fails. The original transistor has shorted out, probably because it was too small of a transistor when they designed it, but that's my opinion. Perhaps a slightly larger transistor might have been in order. And may still very well be.
I'm in the process of fixing one for a friend and as couple people were saying, check and/or replace q4. When doing this, be careful with the copper traces underneath as they are tinier than normal, (as I found out the hard way). However one might need to find a reasonable substitute if all else fails. The original transistor has shorted out, probably because it was too small of a transistor when they designed it, but that's my opinion. Perhaps a slightly larger transistor might have been in order. And may still very well be.
stumbled on this thread.
If your old Bose radio is not working, barely working or otherwise. Open it up and check for stains around the electrolytic capacitors, this is a sign of blown or leaky caps. The Bose wave radio does not turn off when the on/off button is pressed, it just mutes the audio, and so your radio could have been on for 20 plus years.
Most of them are overdue for a complete change of electrolytic capacitors.
to properly repair a generation 1 wave radio you will need for the main board and equalizer board:
22 - 10uf 16v
4 - 1uf 50v
1 - .1uf 50v
4 - 0.47uf 50v
1 - 2.2uf 50v
3 - 3.3uf 50v
3 - 4.7uf 35v
4 - 47uf 16v
2 - 47uf 50v
3 - 100uf 16v
3 - 100uf 25v
1 - 220uf 16v
1 - 470uf 35v
for the display board:
2 - 1uf 50v
1 - 4.7uf 35v
2 - 47uf 16v
1 - 220uf 6.3v
The display board capacitors cannot stick up higher then the display does.
The large 10000uf filter cap usually does not need to be replaced.
more details available here:
Antique Radio Forums • View topic - Bose AWR1-1W Refurbish
If your old Bose radio is not working, barely working or otherwise. Open it up and check for stains around the electrolytic capacitors, this is a sign of blown or leaky caps. The Bose wave radio does not turn off when the on/off button is pressed, it just mutes the audio, and so your radio could have been on for 20 plus years.
Most of them are overdue for a complete change of electrolytic capacitors.
to properly repair a generation 1 wave radio you will need for the main board and equalizer board:
22 - 10uf 16v
4 - 1uf 50v
1 - .1uf 50v
4 - 0.47uf 50v
1 - 2.2uf 50v
3 - 3.3uf 50v
3 - 4.7uf 35v
4 - 47uf 16v
2 - 47uf 50v
3 - 100uf 16v
3 - 100uf 25v
1 - 220uf 16v
1 - 470uf 35v
for the display board:
2 - 1uf 50v
1 - 4.7uf 35v
2 - 47uf 16v
1 - 220uf 6.3v
The display board capacitors cannot stick up higher then the display does.
The large 10000uf filter cap usually does not need to be replaced.
more details available here:
Antique Radio Forums • View topic - Bose AWR1-1W Refurbish
Hi,
Perfectly normal, amplifiers do not go to 10, or 100 in this case.
However 100 should be possible on Aux In by reducing its level.
rgds, sreten.
The wave radio has extremely limited output power capability and was not designed to play extremely loudly. Sufficient gain was provided to allow it to achieve full output with the portable cd players of the time. IIRC the full range amplifier channel is power limited by a compressor circuit that senses when output voltage approaches within a certain % of the available supply rail - its operation was not all that subtle - largely intended to keep from damaging the driver...
Note that driving the amplifier into sustained clipping at 1kHz could damage the drivers so just don't..
Sorry I don't remember more, after 22yrs the memory is very sketchy.
Note that driving the amplifier into sustained clipping at 1kHz could damage the drivers so just don't..
Sorry I don't remember more, after 22yrs the memory is very sketchy.
Can receive FM signals, but no AM stations
I hope someone is still monitoring this old (but very useful) thread...a friend asked me to repair his Wave AWR1-1W (9V battery backup) which had the completely unresponsive w/ the loud crunching noise when unplugging problem...
Replacement of the Q4 transistor w/ the Toshiba transistor referenced above worked...except with one problem...
Everything works (clock set, snooze, alarm, volume, presets, etc.) EXCEPT I can only receive an FM signal (FM sounds flawless - stereo, strong signals)...I cannot get anything from the AM section, completely silent...
I took it outside and moved it around to see if it was weak reception (I'm in an urban environment), but nada...completely silent...
I disassembled unit again to look at the ferrite bar antenna in case i did somthing stupid, but except for the tail end of the four fine wires being slightly shoved in odd spots, I can't see anything wrong with it...under magnifying glass all wires I can see appear intact, the four solder joints into the circuit board APPEAR undamaged...the AM tuner will seek for stations showing the AM frequencies, but it only cycles completely through the band with no found stations, not even a static-filled one...
Is there anything I can do to troubleshoot this issue?
I hope someone is still monitoring this old (but very useful) thread...a friend asked me to repair his Wave AWR1-1W (9V battery backup) which had the completely unresponsive w/ the loud crunching noise when unplugging problem...
Replacement of the Q4 transistor w/ the Toshiba transistor referenced above worked...except with one problem...
Everything works (clock set, snooze, alarm, volume, presets, etc.) EXCEPT I can only receive an FM signal (FM sounds flawless - stereo, strong signals)...I cannot get anything from the AM section, completely silent...
I took it outside and moved it around to see if it was weak reception (I'm in an urban environment), but nada...completely silent...
I disassembled unit again to look at the ferrite bar antenna in case i did somthing stupid, but except for the tail end of the four fine wires being slightly shoved in odd spots, I can't see anything wrong with it...under magnifying glass all wires I can see appear intact, the four solder joints into the circuit board APPEAR undamaged...the AM tuner will seek for stations showing the AM frequencies, but it only cycles completely through the band with no found stations, not even a static-filled one...
Is there anything I can do to troubleshoot this issue?
Arrgh,
yes, apparently, I did do something very stupid...looking around the Net, I found some photos of the AWR1-1W PCB & those 4 wires I see dangling evidently are broken away from soldering posts on the opposite side of the ferrite bar antenna under the rubber foam cushion glued to the top of the ferrite (wow, I don't know how I managed to do that, unless it was during disassembly/reassembly).
Anyway, the posts are numbered 1-4...is there any way to determine which wire goes to which soldering post? Is it critical which wire goes where?
yes, apparently, I did do something very stupid...looking around the Net, I found some photos of the AWR1-1W PCB & those 4 wires I see dangling evidently are broken away from soldering posts on the opposite side of the ferrite bar antenna under the rubber foam cushion glued to the top of the ferrite (wow, I don't know how I managed to do that, unless it was during disassembly/reassembly).
Anyway, the posts are numbered 1-4...is there any way to determine which wire goes to which soldering post? Is it critical which wire goes where?
Yeah...it seems this thread is no longer active...just in case someone is having a similar issue, thought I'd let you know I figured it out...
I searched around the Net until I found a PDF schematic (in my case, for the 1996-era Wave) and obviously the AM antenna is a dual-loopstick ferrite bar, so I used a DMM continuity tester to determine which of the four wires belonged together (1 & 2 and 3 & 4)...
According to the 1996 schematic, posts 1 & 2 take the shorter loop (I used a magnifying glass to visually determine which wires are the short or long loops (low- or high-band AM, I suppose)) and posts 3 & 4 take the longer loop...
Carefully re-routed the insulation-stripped wires to appropriate posts & wrapped them around with tweezers & a fine probe tip, four dabs of solder later & AM reception is fine.
I searched around the Net until I found a PDF schematic (in my case, for the 1996-era Wave) and obviously the AM antenna is a dual-loopstick ferrite bar, so I used a DMM continuity tester to determine which of the four wires belonged together (1 & 2 and 3 & 4)...
According to the 1996 schematic, posts 1 & 2 take the shorter loop (I used a magnifying glass to visually determine which wires are the short or long loops (low- or high-band AM, I suppose)) and posts 3 & 4 take the longer loop...
Carefully re-routed the insulation-stripped wires to appropriate posts & wrapped them around with tweezers & a fine probe tip, four dabs of solder later & AM reception is fine.
Bose wave radio
The only one I ever worked on had no 5V.
Because it did not use a conventional 5V regulator IC and I was on the lazy side, I simply took an old Cell Phone charger, stuck it inside, soldered wires to the AC plug part, over to the AC line cord pads, and used heat shrink tubing to insulate for safety. I then soldered the ground to ground and the red wire to the 5V end of the output of the blown transistor. It worked, everything, slapped it all back together and let ir run overnight with no issues whatsoever.
The thing is later after I looked at the schematic to see that they took and created the 5V from the 12V source, using a zener diode, resistor etc. I just removed the pass transistor so that eliminated any possible problems and isolated it all. I think mainly that they just under engineered the 5V regulator to not be able to supply enough current, is why it blew.
Like all electronic devices it was probably the weak link in the design.
Yeah this thread is old but others may benfit from this. Yes you can get PDF schematic. I just could not find source of parts, so I went the cheap route.
Often can get used old cell phone chargers from Goodwill or Salvation army, that make useful low current sources for 5V. Just cut off the plug strip back wires. Then you could also if desired just buy and old cheap extension cord, and cut the outlet end leaving enough wire, to solder it into AC line cord inside unit. Or cur off the end from an old defunct set of Christmas lights socket, and use that. Just make sure it is safe and fits inside whatever device you are fixing.
The only one I ever worked on had no 5V.
Because it did not use a conventional 5V regulator IC and I was on the lazy side, I simply took an old Cell Phone charger, stuck it inside, soldered wires to the AC plug part, over to the AC line cord pads, and used heat shrink tubing to insulate for safety. I then soldered the ground to ground and the red wire to the 5V end of the output of the blown transistor. It worked, everything, slapped it all back together and let ir run overnight with no issues whatsoever.
The thing is later after I looked at the schematic to see that they took and created the 5V from the 12V source, using a zener diode, resistor etc. I just removed the pass transistor so that eliminated any possible problems and isolated it all. I think mainly that they just under engineered the 5V regulator to not be able to supply enough current, is why it blew.
Like all electronic devices it was probably the weak link in the design.
Yeah this thread is old but others may benfit from this. Yes you can get PDF schematic. I just could not find source of parts, so I went the cheap route.
Often can get used old cell phone chargers from Goodwill or Salvation army, that make useful low current sources for 5V. Just cut off the plug strip back wires. Then you could also if desired just buy and old cheap extension cord, and cut the outlet end leaving enough wire, to solder it into AC line cord inside unit. Or cur off the end from an old defunct set of Christmas lights socket, and use that. Just make sure it is safe and fits inside whatever device you are fixing.
Thanks guys, for help on this. I replaced Q4 with 2SC3068 (the closest I could find for now $0.45) and the radio is back in service.
I will continue to look for a closer match to SC3792 or SC2655, but for now I am good.
I took the radio to a high end stereo store in Toronto where they do repairs and they told me they do not repair Bose, but can send it to Bose, except that my unit is too old (it was manufactured June 16, 1998) and Bose would not fix it either. They would offer me a "special price" on a new unit. The new units are made in China, have no control buttons on the top, and come in an ugly black/grey colour. No thanks...
I will continue to look for a closer match to SC3792 or SC2655, but for now I am good.
I took the radio to a high end stereo store in Toronto where they do repairs and they told me they do not repair Bose, but can send it to Bose, except that my unit is too old (it was manufactured June 16, 1998) and Bose would not fix it either. They would offer me a "special price" on a new unit. The new units are made in China, have no control buttons on the top, and come in an ugly black/grey colour. No thanks...
My Bose Wave Radio lit up all indicators and lost all controls. I unplugged it in and it made sound in the speakers. After waiting a long time and plugging back in everything was dead. But still makes a sound from the speakers when unplugged. From what I can understand it sounds like the Q4 transistor may need to be replaced but I can not find it. Where is the Q4 Transistor located on the AWR1-1W Bose Wave Radio?
I am currently servicing my Bose Acoustic Wave model number AW-1. Ilove it for travel as it is better than most hotel radios. I found an open trace and repaired that so the unit works EXCEPT, the LF (sub woofer) in it sounds farty (insert Bose insult here.) It is impossible to listen to it this way. I'm not sure what it is, but it might be a cap, resistor, transistor. Does anyone have any experience with this unit? I can't find a schematic for it which would go a long way toward tracing the issue. Help? Please?
I always thought Bose was a form of the German word böse, which means bad or wicked.
John
Many thanks to JenJohn. Same symptoms with one here...totally dead, with a short noise burst when unplugged. A bunch of caps had gone high ESR, as usual (replaced), and (of course) a shorted Q4. Ordered some 2SC2566 replacements on-line...works like a champ now.
Some of the high ESR caps were right near Q4. Makes me wonder if when those get weak, extra stress is placed on that transistor.?. I also wonder if the rating is higher on the 2655 than the original.
Some of the high ESR caps were right near Q4. Makes me wonder if when those get weak, extra stress is placed on that transistor.?. I also wonder if the rating is higher on the 2655 than the original.
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