Old Receiver

Bose(o) · 20th November 2004, 10:51 PM

Hello all!

I have an old receiver from my Dad and the right channel is heavily distorted. Anyway, I've measured the amps and regulators...nothing looks black or brown. Found a grounding problem and fixed that.

Now it doesn't go POP! when you turn it on.

However I found one of the chips, not exactly sure what it is yet, measuring out of spec with the others in the circuit. The following is written on the chip (B699 BL3). I'm hoping it'll ring a bell in someon's head.

I know the amp was built in the mid 70's. I just need to find some kind of replacement for the ONE bad chip.

TIA, Brodey Dover

EE student at Univeristy of Ottawa

EchoWars · 21st November 2004, 12:03 AM

Sounds like a 2SB699 transistor... 160V, 12A, 100W.

What you you mean, 'measures out of spec'?

Bose(o) · 21st November 2004, 12:08 AM

If I measure from Ground and ouptut of the transistor then I'd get a resistance value below that of the other transistor's on the circuit.

Receiver is rated 100W RMS, I'll check it out.

EchoWars · 21st November 2004, 01:38 AM

Pull the transistor and do a diode check on the thing.

Bose(o) · 21st November 2004, 07:06 PM

Diode checks: Pins on transistors go like CBE? Collector base emitter?

Would the diode check be between the Collector and Emitter.

I appreciate your help.

EchoWars · 21st November 2004, 11:09 PM

Diode check from base to emitter, then from base to collector. Both should show a standard forward voltage drop...something like 0.4V to 0.7V. With an NPN transistor, positive on the base and negative on the emitter and collector. Then check collector to emitter, first with positive on the collector and negative on the emitter, then reverse...negative on collector and positive on emitter. Should read nothing measuring from collector to emitter.

Of course, check a PNP transistor with the leads reversed...negative on the base and positive on the collector and emitter... Same deal with the collector to emitter check, there should be no conducting with the leads in any configuration.

Bose(o) · 26th November 2004, 06:17 PM

Okay, its BCE.

BE measures as: 0.518V

Shall I check others?

Bose(o) · 26th November 2004, 06:58 PM

30 min. limit to edit messages grrr...

Okay, its BCE.

BE measures as for B699 chips:
1. 0.518V
2. 0.520V
3. 0.522V
4. 0.521V (So, all 699 chips are good).

Bose(o) · 26th November 2004, 07:22 PM

D735 chips are NPN, 699s are PNP.

1. 0.521V
2. 0.528V
3. 0.528V
4. 0.530V

The main problem was a HEAVILY distorted right-channel. Left-channel was beautiful. I thought that distortions that I was hearing would be caused by the transistors.

Bose(o) · 26th November 2004, 08:20 PM

Wow...sorry guys.

I either can't type or see or, both.

Anyway the 699s read as:
1.0.537V
2.0.531V
3.0.527V
4.0.521V

I do believe that +/- 0.016 V shouldn't matter much, but that's my opinion. What do you guys think?

20th November 2004, 10:51 PM	#1
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	Old Receiver Hello all! I have an old receiver from my Dad and the right channel is heavily distorted. Anyway, I've measured the amps and regulators...nothing looks black or brown. Found a grounding problem and fixed that. Now it doesn't go POP! when you turn it on. However I found one of the chips, not exactly sure what it is yet, measuring out of spec with the others in the circuit. The following is written on the chip (B699 BL3). I'm hoping it'll ring a bell in someon's head. I know the amp was built in the mid 70's. I just need to find some kind of replacement for the ONE bad chip. TIA, Brodey Dover EE student at Univeristy of Ottawa __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild

21st November 2004, 12:08 AM	#3
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	If I measure from Ground and ouptut of the transistor then I'd get a resistance value below that of the other transistor's on the circuit. Receiver is rated 100W RMS, I'll check it out. __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild

21st November 2004, 07:06 PM	#5
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	Diode checks: Pins on transistors go like CBE? Collector base emitter? Would the diode check be between the Collector and Emitter. I appreciate your help. __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild

26th November 2004, 06:17 PM	#7
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	Okay, its BCE. BE measures as: 0.518V Shall I check others? __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild

26th November 2004, 06:58 PM	#8
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	30 min. limit to edit messages grrr... Okay, its BCE. BE measures as for B699 chips: 1. 0.518V 2. 0.520V 3. 0.522V 4. 0.521V (So, all 699 chips are good). __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

21st November 2004, 12:03 AM	#2
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Sounds like a 2SB699 transistor... 160V, 12A, 100W. What you you mean, 'measures out of spec'?

21st November 2004, 01:38 AM	#4
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Pull the transistor and do a diode check on the thing.

21st November 2004, 11:09 PM	#6
EchoWars diyAudio Member Join Date: Dec 2002 Location: Left of the Dial	Diode check from base to emitter, then from base to collector. Both should show a standard forward voltage drop...something like 0.4V to 0.7V. With an NPN transistor, positive on the base and negative on the emitter and collector. Then check collector to emitter, first with positive on the collector and negative on the emitter, then reverse...negative on collector and positive on emitter. Should read nothing measuring from collector to emitter. Of course, check a PNP transistor with the leads reversed...negative on the base and positive on the collector and emitter... Same deal with the collector to emitter check, there should be no conducting with the leads in any configuration.

26th November 2004, 07:22 PM	#9
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	D735 chips are NPN, 699s are PNP. 1. 0.521V 2. 0.528V 3. 0.528V 4. 0.530V The main problem was a HEAVILY distorted right-channel. Left-channel was beautiful. I thought that distortions that I was hearing would be caused by the transistors. __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild

26th November 2004, 08:20 PM	#10
Bose(o) diyAudio Member Join Date: Dec 2001 Location: Ottawa, Ontario, Canada	Wow...sorry guys. I either can't type or see or, both. Anyway the 699s read as: 1.0.537V 2.0.531V 3.0.527V 4.0.521V I do believe that +/- 0.016 V shouldn't matter much, but that's my opinion. What do you guys think? __________________ ERTW 4 life! "the day has 24hours. If that is not enough take the night."-Roemhild

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
FS: JVC RX-ES1 receiver	tf1216	Swap Meet	0	7th February 2009 09:16 PM
DIY AM/FM receiver	emuman100	Analogue Source	0	4th October 2004 01:49 AM
Hey i need help with receiver........EXPERTS HELP(two channel receiver)	Andre Baptiste	Parts	1	1st May 2004 10:20 AM
Need help : DIY Fm car receiver	darkm4n	Car Audio	7	17th January 2004 01:02 PM
diy receiver	Randy Knutson	Digital Source	0	15th January 2004 06:20 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read