Hey;

I just got this original 1971 Chrysler radio but it has distorted audio.
( Chrysler 3501013 Mark 07902)
Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and it looks like 7252 respectively.

I've been trying to identify them (here's a pic)
http://i582.photobucket.com/albums/s...o/MVC-205F.jpg

I wonder if anyone is old enough or experienced with these to help.
Thanks in advance.

Spark

On Tue, 4 Sep 2012 04:32:44 -0700 (PDT), Sparkey wrote:

I just got this original 1971 Chrysler radio but it has distorted audio.
( Chrysler 3501013 Mark 07902)
Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and
it looks like 7252 respectively.

I'd have to believe those are date codes, Spark.

Jonesy

Sparkey wrote in message
...
Hey;

I just got this original 1971 Chrysler radio but it has distorted audio.
( Chrysler 3501013 Mark 07902)
Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and it
looks like 7252 respectively.

I've been trying to identify them (here's a pic)
http://i582.photobucket.com/albums/s...o/MVC-205F.jpg

I wonder if anyone is old enough or experienced with these to help.
Thanks in advance.

Spark


I would find a complementary (on the assumption 2 different datecodes) pair
of TO126, 3 or 4A, 50 V or so transistors and jury-rig, in the first
instance.
1972 datecodes probably

Sparkey wrote:

Hey;

I just got this original 1971 Chrysler radio but it has distorted audio.
( Chrysler 3501013 Mark 07902)


Sam's list six 3501013 versions:
Volume Date On hand
3501013 (1BBC) 89 1971 Y
3501013 (GG01303) 104 1971 Y
3501013 (PG 73) 122 1972 Y
3501013 (1PD1209, 2DP1209) 128 1972 Y
3501013 (2PD1308) 157 1973 Y
3501013 179 1974 Y


Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and it looks like 7252 respectively.


Date codes: 39th & 52 week of 1972


I've been trying to identify them (here's a pic)
http://i582.photobucket.com/albums/s...o/MVC-205F.jpg


I get: "Status 503 Service Unavailable"

I would think it would be in one of the last two manuals listed, but
I'd like to see some photos beore I dig out the books.

On Sep 4, 4:32*am, Sparkey wrote:
Hey;

* I just got this original 1971 Chrysler radio but it has distorted audio.
( *Chrysler 3501013 *Mark 07902)
Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and it looks like 7252 respectively.

I've been trying to identify them (here's a pic)http://i582.photobucket.com/albums/s...o/MVC-205F.jpg


This is the craziest photo I've ever seen, if you want people to ID
the transistor. Can you take a pic that's closer to 90 degrees than to
150? I would like to see what the three digit numbers are in the
corner.

On Tuesday, September 4, 2012 4:32:45 AM UTC-7, Sparkey wrote:

I just got this original 1971 Chrysler radio but it has distorted audio.

Turns out that one of the 2 output transistors is shorted.

If the (working) one is not a Darlington, it's probably a complementary
pair (one NPN, one PNP); modern equivalent-or-better would be MJE243 and MJE253;
replace both and you can be assured the pair is truly complementary.

It's unlikely the 1971 transistor was of any type currently produced.

On Sep 4, 11:40*am, "Michael A. Terrell"
wrote:
Sparkey wrote:

Hey;

* I just got this original 1971 Chrysler radio but it has distorted audio.
( *Chrysler 3501013 *Mark 07902)

* *Sam's list six 3501013 versions:
* * * * * * * * * * * * * * * * Volume *Date * *On hand
3501013 (1BBC) * * * * * * * * * 89 * * 1971 * *Y
3501013 (GG01303) * * * * * * * 104 * * 1971 * *Y
3501013 (PG 73) * * * * * * * * 122 * * 1972 * *Y
3501013 (1PD1209, 2DP1209) * * *128 * * 1972 * *Y
3501013 (2PD1308) * * * * * * * 157 * * 1973 * *Y
3501013 * * * * * * * * * * * * 179 * * 1974 * *Y

Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and it looks like 7252 respectively.

Date codes: 39th & 52 week of 1972

Guess he's wrong about it being a 1971 radio then. If anything the
date codes would be 1970, not 1972.

But why would they put the date code next to the logo?


I've been trying to identify them (here's a pic)
http://i582.photobucket.com/albums/s...o/MVC-205F.jpg

* *I get: "Status 503 Service Unavailable"

Mee too, the first few times.


* *I would think it would be in one of the last two manuals listed, but
I'd like to see some photos beore I dig out the books.

If you want a good picture of leads on a power tab package you're in
luck.

Go to Digikey, they have a selector, get something with gain like 100-300, Vcex about 25, 5 amps and 50 watts Pd and you'll ne fine.

The only thing is this is going to be a low feedback design so if the originals were germanium you need to give it more bias. In fact I am almost sure tht one is shorted B-E from your symptom. Look at that driver circuit, ot might need something, likely a small resistor.

There just ain't that much power there.

T

spamtrap1888 wrote:

On Sep 4, 11:40 am, "Michael A. Terrell"
wrote:
Sparkey wrote:

Hey;

I just got this original 1971 Chrysler radio but it has distorted audio.
( Chrysler 3501013 Mark 07902)

Sam's list six 3501013 versions:
Volume Date On hand
3501013 (1BBC) 89 1971 Y
3501013 (GG01303) 104 1971 Y
3501013 (PG 73) 122 1972 Y
3501013 (1PD1209, 2DP1209) 128 1972 Y
3501013 (2PD1308) 157 1973 Y
3501013 179 1974 Y

Turns out that one of the 2 output transistors is shorted.

Both transistors have the Motorola icon and have the numbers 7239 and it looks like 7252 respectively.

Date codes: 39th & 52 week of 1972

Guess he's wrong about it being a 1971 radio then. If anything the
date codes would be 1970, not 1972.


Motorola used the industry standard of a two digit year, followed by the
two digit week.


All in that series would fit a '71 though '74 model. It may have
been pulled out of a newer vehicle to replace the original, or a used
car dealer may have bought it from a junk yard to put it in a car with
no radio.


But why would they put the date code next to the logo?


House numbered parts. OEM car radios were full of them. I repaired
thousands of the things in the early and mid '70s, and maybe 100 in the
mid '60s while I was still in school.

They used a six digit part number for all of the transistors, and
only marked the last three digits

There are several different sets listed:

359091 NTE 182 Q6
359092 NTE 196 Q7 ****** Looks like this was used.
or
359100 NTE 183 Q6
359101 NTE 197 Q7 ****** Looks like this was used.


I would check Q4 & Q5 before replacing the bad output, along with the
..31 Ohm fusible emitter resistors R35 & R36.

359117 NTE 123A Q4
359063` NTE 159 Q5
or
359116 NTE 123A Q4
359118` NTE 159 Q5


I would see if NTE has changed the replacement numbers in the last 40
years, before buying the parts.



359107 R35 & R36 .31 Ohm Wire wound with no wattage listed. From the
photo, I would use a two or three watt if either are open.

If the part numbers don't match, I will dig out the older manuals, but
this is a dirt simple complimentary audio amp.

I've been trying to identify them (here's a pic)
http://i582.photobucket.com/albums/s...o/MVC-205F.jpg

I get: "Status 503 Service Unavailable"

Me too, the first few times.


I've tried, for several hours with no luck. I just tried again, and
got the photo, but it isn't much use.


I would think it would be in one of the last two manuals listed, but
I'd like to see some photos beore I dig out the books.

If you want a good picture of leads on a power tab package you're in
luck.

wrote:

Go to Digikey, they have a selector, get something with gain like 100-300, Vcex about 25, 5 amps and 50 watts Pd and you'll ne fine.

The only thing is this is going to be a low feedback design so if the originals were germanium you need to give it more bias. In fact I am almost sure tht one is shorted B-E from your symptom. Look at that driver circuit, ot might need something, likely a small resistor.

There just ain't that much power there.


Motorola never made Germanium power transistors in a flat epoxy
package.

"Michael A. Terrell" wrote in message
m...

wrote:

Go to Digikey, they have a selector, get something with gain like
100-300, Vcex about 25, 5 amps and 50 watts Pd and you'll ne fine.

The only thing is this is going to be a low feedback design so if the
originals were germanium you need to give it more bias. In fact I am
almost sure tht one is shorted B-E from your symptom. Look at that driver
circuit, ot might need something, likely a small resistor.

There just ain't that much power there.


Motorola never made Germanium power transistors in a flat epoxy
package.

I don't think anyone did.

BTW, you would be surprised at how much it cost to make that radio. Less
than $5 back then.

tm

Thanks for all the input.

I apologize for the pic, I know that photobucket was acting squirrely even when I was uploading this.

I will check on those NTE 196 and 197.
The resistors that you mention appear to be good. So far, it's only that one transistor that went out.

Yeah, this radio came out of a "1971 Chrysler". Not surprised it good have been replaced or swapped with a newer one somewhere along the way.

Spark...