This is my first posting here, and I'm hoping it's appropriate for this forum.
I've been working on my father's Heathkit AR-14 that he built around 1967 or 1968. It's worked well within my memory. Daddy used it as a garage radio when I was growing up. About 18 or so years ago, one of my brothers brought it in and used it for a stereo amp until it blew a cap. I took possession more recently with the goal of repairing and using it.
The last capacitors arrived today, so a significant number, though not every last one, of the caps have been replaced. All the caps replaced have been on the power supply board. These included 2 2700uF caps that were replaced with 4700uF at higher voltage and four 100uF 30v that were replaced with 100uF 50v, and six others whose values I can't remember right now. One of the 100uF 30v had exploded at some point in the past.
I hooked up an antenna and speakers and my phono for good measure and pulled the power switch out. Amp lights up, makes that "turn-on" sound, and I switched the Source switch to FM Stereo. Tuned the dial and the Tuning light lit up and flickered when appropriate, but I couldn't hear anything. Turned the volume way up, and I *might* have been able to hear a little something. Turned it back down and plugged a nice set of ATH-M40 headphones into the jack. There was a consistent hiss in both ears. The sound was inaudible until I turned the volume really high.
When switched to phono, the sound is quiet and seems tinny. The radio sound has some nice depth, but not enough volume.
So I unplugged everything and took a look at the solder joints I'd made during the cap swap. A couple looked suspect, so I reheated and re-flowed them. Then, I used electronic cleaner on all the switches. After that, I hooked everything back up for another go. Well, it might be a little better, and the volume sounds louder, but it still takes turning it nearly to the top to get much of anything. I know these amps weren't the most powerful in the Heathkit lineup, but this seems a bit low by any standards.
To make matters worse, I must have bridged a contact while checking conductivity cause the transistor labeled Q100 on the schematic blew up.
I'm generally able to understand schematics and stuff like that, but I'm not sure what to look at or do next. Feels like I'm right on the verge of getting it right.
Any assistance and suggestions for potential upgrades would be appreciated. Daddy will be proud to see his amp working again.
Thank you,
-William
Sent from my myTouch_4G_Slide using Tapatalk 2
I've been working on my father's Heathkit AR-14 that he built around 1967 or 1968. It's worked well within my memory. Daddy used it as a garage radio when I was growing up. About 18 or so years ago, one of my brothers brought it in and used it for a stereo amp until it blew a cap. I took possession more recently with the goal of repairing and using it.
The last capacitors arrived today, so a significant number, though not every last one, of the caps have been replaced. All the caps replaced have been on the power supply board. These included 2 2700uF caps that were replaced with 4700uF at higher voltage and four 100uF 30v that were replaced with 100uF 50v, and six others whose values I can't remember right now. One of the 100uF 30v had exploded at some point in the past.
I hooked up an antenna and speakers and my phono for good measure and pulled the power switch out. Amp lights up, makes that "turn-on" sound, and I switched the Source switch to FM Stereo. Tuned the dial and the Tuning light lit up and flickered when appropriate, but I couldn't hear anything. Turned the volume way up, and I *might* have been able to hear a little something. Turned it back down and plugged a nice set of ATH-M40 headphones into the jack. There was a consistent hiss in both ears. The sound was inaudible until I turned the volume really high.
When switched to phono, the sound is quiet and seems tinny. The radio sound has some nice depth, but not enough volume.
So I unplugged everything and took a look at the solder joints I'd made during the cap swap. A couple looked suspect, so I reheated and re-flowed them. Then, I used electronic cleaner on all the switches. After that, I hooked everything back up for another go. Well, it might be a little better, and the volume sounds louder, but it still takes turning it nearly to the top to get much of anything. I know these amps weren't the most powerful in the Heathkit lineup, but this seems a bit low by any standards.
To make matters worse, I must have bridged a contact while checking conductivity cause the transistor labeled Q100 on the schematic blew up.
I'm generally able to understand schematics and stuff like that, but I'm not sure what to look at or do next. Feels like I'm right on the verge of getting it right.
Any assistance and suggestions for potential upgrades would be appreciated. Daddy will be proud to see his amp working again.
Thank you,
-William
Sent from my myTouch_4G_Slide using Tapatalk 2
posting schematics would allow the group to help you. Do you have them in a postable format? Or, a link to the schematics would be good.
Here's a long-shot...any chance the tape monitor switch is activated (assuming it has one)? That would break the sound path in a way that you describe.
The general path to repair these kinds of things is signal substitution or tracing...so if you have another good amp, that could help.
Update My Dynaco
Akitika GT-101 Audio Power Amplifier Kit
Here's a long-shot...any chance the tape monitor switch is activated (assuming it has one)? That would break the sound path in a way that you describe.
The general path to repair these kinds of things is signal substitution or tracing...so if you have another good amp, that could help.
Update My Dynaco
Akitika GT-101 Audio Power Amplifier Kit
Ok, this is just one of the schematics I've found for this amp. Trying to figure out which one is the easiest to read.
HEATH KIT AR-14 SCHEMATIC DIAGRAM Pdf Download.
The amp doesn't have a tape monitor. It's pretty basic, with M and S aux input, M and S FM, and M and S phono input.
Would this amp require a pre-amp for a post-60s turntable to work properly?
Thank you,
-William
HEATH KIT AR-14 SCHEMATIC DIAGRAM Pdf Download.
The amp doesn't have a tape monitor. It's pretty basic, with M and S aux input, M and S FM, and M and S phono input.
Would this amp require a pre-amp for a post-60s turntable to work properly?
Thank you,
-William
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