Thank you so much for a very interesting video. I have a DR29 that was sitting at a recycling station here in Sweden. It has no lightning and the battery and tuning meter is completely dead. However, it takes in stations on the FM band very well. Crystal clear sound, but the volume knob is quite choppy I can hardly wait for part 3. Thank you very much
I was wondering if you considered replacing those bulbs with LED's while it was all apart as it seems your luck is about the same as mine. Put it all back together and the bulb burns out. Those looks like the same type of bulb that was used to light up the dial on stereo tuners of the day. Since it's quite a bit of work to get to them I think I would go the LED route simply for longevity's sake. Looking forward to part 3. ATB Doug.
Hi Doug, that's next on the hit list, one or two LEDs to light it up like a Christmas tree! :) Yes, I've had to replace several of the fuse lamps in a couple of stereo receivers I had ages ago. Not an easy job as the whole front needed to come off.
I got one of this when I visited srilanka. One guy was trying to sell this scrap on the foot path in Colombo. Happily he sold it to me for $ 2.That was 20 years ago. I was surprised to see smd components inside freqency display. It's digital display, amplifier board, power supply are working. Since last 20 years I am experimenting with it. It's main board consisting of rf amp, mixers, detectors etc is in very bad state. Some sections burnt and repaired previously. Insulators inside the tuning capacitor has crumbled. I have repaired the fm front end only. The IC, an7212, An7210 an7211 are not available. I Coul manage to get the schematic recently on the net which is not clear but helpful. Don't know if I can fix it.
Hi Mike, no :) Too many projects on the go. This one will find it's way back on the bench though as it needs aligning and I will also convert lighting to LED.
I do not think you have a problem with the lamp dimming on high level. After all it is fed from a un stabilised supply. The amplifier is probably class B and the current draw on low volume would be probably 30mA or so but in high volume could well be 100/150mA so the voltage WILL sag. You could use an LED which will not show the voltage change so much and use a lot less power on battery use. It is the amplifier current draw you are seeing, not much you can do about that!
Hi Michael, you're quite right it is a class B amp. Have to say I've not seen the dimming effect this band before, it's just really noticeable hence my dive in for the capacitors.
I have used the ESR meter, (a kit from Electronics Australia) and make comparisons between the ESR of the new electrolytic capacitor, and the old one. Often on the lower values, (working voltage and capacitance) the ESR reads higher with the original capacitor in circuit, and therefore 'replace', but Panasonic (Matsushita Electric) radios of that vintage have very reliable electrolytic capacitors, so an ESR of 1.68 ohms would not stop it from functioning, given the volume control is a some kilohms... A 'freeze' test would ascertain an electrolytic capacitor fault..
They do have reliable capacitors in in general but this was the first one I pulled and tested that showed In Circuit when out of circuit. Anyway, someone will never have to replace that again :)
Yes, quite right. Over several TV repairs, I've found the most unreliable passive components are electrolytic capacitors. I barely did any work with 'tube' or 'valve' circuits, and it seems they had problems with the higher voltage wax/paper types as well.
Fab video Andrew. Lots of dismantling to find the dodgy cap! I really like Panasonic gear. Their caps are very highly quality and rarely fail. Will you change the lamps to LEDs or keep it original? Nice work. Thanks for taking the time to document it.
Hi Cliff, part three is...err..not even filmed yet. Too many exciting projects arriving, too little time. The radio is still technically 'on the bench' though as it's sitting behind me!
This one was the unknowing bit, the expectation that any second a spring could go flying across the room that you couldn't see where it came from. It was actually way easier than I thought to remove that tuning section, very cleverly designed.
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Thank you so much for a very interesting video. I have a DR29 that was sitting at a recycling station here in Sweden. It has no lightning and the battery and tuning meter is completely dead. However, it takes in stations on the FM band very well. Crystal clear sound, but the volume knob is quite choppy I can hardly wait for part 3. Thank you very much
You have a great hobby. The main thing is that you like it.
Keep up the good work. From an ex Pye test technician ( St Andrews road site)
I'm very near Cambridge, Pye radio or the Pye/Philips telecom bit?
I was wondering if you considered replacing those bulbs with LED's while it was all apart as it seems your luck is about the same as mine. Put it all back together and the bulb burns out. Those looks like the same type of bulb that was used to light up the dial on stereo tuners of the day. Since it's quite a bit of work to get to them I think I would go the LED route simply for longevity's sake. Looking forward to part 3. ATB Doug.
Hi Doug, that's next on the hit list, one or two LEDs to light it up like a Christmas tree! :) Yes, I've had to replace several of the fuse lamps in a couple of stereo receivers I had ages ago. Not an easy job as the whole front needed to come off.
Good work
I got one of this when I visited srilanka. One guy was trying to sell this scrap on the foot path in Colombo. Happily he sold it to me for $ 2.That was 20 years ago. I was surprised to see smd components inside freqency display. It's digital display, amplifier board, power supply are working. Since last 20 years I am experimenting with it. It's main board consisting of rf amp, mixers, detectors etc is in very bad state. Some sections burnt and repaired previously. Insulators inside the tuning capacitor has crumbled. I have repaired the fm front end only. The IC, an7212, An7210 an7211 are not available. I Coul manage to get the schematic recently on the net which is not clear but helpful. Don't know if I can fix it.
Hello, excellent tutorial. Buy the way, did you finally get the problem fixed ?
Hi Mike, no :) Too many projects on the go. This one will find it's way back on the bench though as it needs aligning and I will also convert lighting to LED.
I do not think you have a problem with the lamp dimming on high level. After all it is fed from a un stabilised supply. The amplifier is probably class B and the current draw on low volume would be probably 30mA or so but in high volume could well be 100/150mA so the voltage WILL sag. You could use an LED which will not show the voltage change so much and use a lot less power on battery use. It is the amplifier current draw you are seeing, not much you can do about that!
Hi Michael, you're quite right it is a class B amp. Have to say I've not seen the dimming effect this band before, it's just really noticeable hence my dive in for the capacitors.
I have used the ESR meter, (a kit from Electronics Australia) and make comparisons between the ESR of the new electrolytic capacitor, and the old one. Often on the lower values, (working voltage and capacitance) the ESR reads higher with the original capacitor in circuit, and therefore 'replace', but Panasonic (Matsushita Electric) radios of that vintage have very reliable electrolytic capacitors, so an ESR of 1.68 ohms would not stop it from functioning, given the volume control is a some kilohms... A 'freeze' test would ascertain an electrolytic capacitor fault..
They do have reliable capacitors in in general but this was the first one I pulled and tested that showed In Circuit when out of circuit. Anyway, someone will never have to replace that again :)
Yes, quite right. Over several TV repairs, I've found the most unreliable passive components are electrolytic capacitors. I barely did any work with 'tube' or 'valve' circuits, and it seems they had problems with the higher voltage wax/paper types as well.
Did I see a pic of unlucky Alf and his swearing pet bird? great video as ever. Be lucky.
You did :) That's how I felt!!
@@Andrewausfa I know that feeling only too well "Oh Bugger" ;-)
Fab video Andrew. Lots of dismantling to find the dodgy cap! I really like Panasonic gear. Their caps are very highly quality and rarely fail. Will you change the lamps to LEDs or keep it original? Nice work. Thanks for taking the time to document it.
I'm going to put LEDs in Victor. Yep, I use Panasonics in almost everything from valve stuff to transistors, never an issue.
Can you clean arm board with isopropyl use as spry?
wheres part 3? followup?
Hi Cliff, part three is...err..not even filmed yet. Too many exciting projects arriving, too little time. The radio is still technically 'on the bench' though as it's sitting behind me!
Bugger indeed my thoughts exactly.
What about a better speaker? Mine says only Panasonic on the grill not International...?
simple jobs are never easy, yet the ones you dread go smoothly. There is no such thing as a 5 minute job in radios though...
This one was the unknowing bit, the expectation that any second a spring could go flying across the room that you couldn't see where it came from. It was actually way easier than I thought to remove that tuning section, very cleverly designed.
Well doesn't it figure the bulb popping when it's all back together!
Like
semm .may redio
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