Thanks Steve ill dig out the datasheet for the TBA810 as i want to understand what it does in the radio apart from the audio output. It is indeed a very nice set and well made and sounds very good even with my hacked together output stage. Get it out in the garden away from interference and its performance is excellent.
@@Jayoldstuff1 Steveuk405 probably gave incorrect answer. The audio amplifier IC in VEGA 404 is К174УН4Б rather than К174УН9. К174УН4Б=TAA300 К174УН7=TBA810 К174УН9=TCA940 You can try to find TAA300 (Mullard, Signetics, etc.), probably it will be correct replacement, but the cases and pinouts are different.
The little Signal is a nice radio, I used one as an alarm clock for a few years. Like you, I usually don't just change electolytics but as you're in there you may as well.
57:40 I remember trying to do that with an LM-383 back in the 1970s and for some reason, it never worked very well. From what I've read since, the 383s tended to ring like crazy and distort if the supporting parts were not arranged just so, and it was better to either use it with a pre-etched daughter board or to just buy one of those hybrid amplifier modules that were sealed in goop. There was also a modified LM-383 configuration that gave up some performance for more stability. Maybe the LM-386 is a little less squirrelly.
For the capacitor polarity: There is a + sign on the bottom seal plastic, visible only from the bottom. No reliable polarity marking on the aluminium can itself...
33:57 on these capacitors, the polarity was indicated directly on the bottom plug, around the leg leads. If you were a little more careful, you would have noticed the castings in the form of + and - A very smart solution was to use a separate amplifier on the board. But I was hoping for the rest of the video that you would build a smaller board in place of the legs of the original amplifier chip. I may have missed the moment where you disconnected the faulty microcircuit from the power supply, as it can consume current. Moreover, in a faulty condition, it will drain the battery much faster. ))
those simple cap testers can give incorrect readings if the cap has any resistive leakage or high esr, and as for the cap testing high, DOESNT necessarily mean its bad , could be because its hasnt had power on it for years and deformed, if so it will appear 'leaky' or 'lossy' to one of those testers, try reforming it to max volts first, then discharge, also many caps had wide positive tolerance, i've seen some specified as +80%, -20% !
I guess you could have stopped the video, backed it up to see that the paint spot was facing out...I was going over old video's I watched and seen this one, which I liked.
Mark the caps before taking them out...or take a pic...I have dont this before...and sure everyone else has too...in the video the red mark can be seen, oh and I always check the earphone jack first to see if it is stuck open.......thanks for the video...
If the aim was a concours restoration the you would be right, however Jay said right at the start that the aim here was just to get some sound out of it. The alternative is that it ends up in a landfill site. He clearly explained that the cost of a proper repair was uneconomical.
![Electronic Circuitry Diagnosis And Fault Finding! [Repair]](http://i.ytimg.com/vi/LC7OjuYAOQE/mqdefault.jpg)
Good job! When I was a child have VEGA-402 (older model) Now l remade my radio to FM, because nothing on AM in Russia.
The chip in this is a К174УН9 and can be replaced with a TBA810 in most cases. Very nice sets those.
Thanks Steve ill dig out the datasheet for the TBA810 as i want to understand what it does in the radio apart from the audio output. It is indeed a very nice set and well made and sounds very good even with my hacked together output stage. Get it out in the garden away from interference and its performance is excellent.
@@Jayoldstuff1 Steveuk405 probably gave incorrect answer. The audio amplifier IC in VEGA 404 is К174УН4Б rather than К174УН9. К174УН4Б=TAA300
К174УН7=TBA810
К174УН9=TCA940
You can try to find TAA300 (Mullard, Signetics, etc.), probably it will be correct replacement, but the cases and pinouts are different.
@@ЕленаМаксимова-л7ц8и TBA820M I think. LM386 will do too different pinouts
Very well done - its not an easy task to record a video and commentate and go through troubleshooting a radio all at the same time !
Top notch as always Jay
Nice repair I did the same mod to that fidelity radio master top one mate
Awesome! Good diagnosis
The little Signal is a nice radio, I used one as an alarm clock for a few years. Like you, I usually don't just change electolytics but as you're in there you may as well.
nice one jay.
The springs on battery plate use to grab the contact stripes of two 3R12 lantern batteries.
nice, looks like an 'updated' version of the model 402 !
57:40 I remember trying to do that with an LM-383 back in the 1970s and for some reason, it never worked very well. From what I've read since, the 383s tended to ring like crazy and distort if the supporting parts were not arranged just so, and it was better to either use it with a pre-etched daughter board or to just buy one of those hybrid amplifier modules that were sealed in goop. There was also a modified LM-383 configuration that gave up some performance for more stability. Maybe the LM-386 is a little less squirrelly.
For the capacitor polarity: There is a + sign on the bottom seal plastic, visible only from the bottom. No reliable polarity marking on the aluminium can itself...
So did you end up using the 1K resistor? Incidentally my first thought was a 386 as well.
33:57 on these capacitors, the polarity was indicated directly on the bottom plug, around the leg leads. If you were a little more careful, you would have noticed the castings in the form of + and -
A very smart solution was to use a separate amplifier on the board. But I was hoping for the rest of the video that you would build a smaller board in place of the legs of the original amplifier chip.
I may have missed the moment where you disconnected the faulty microcircuit from the power supply, as it can consume current.
Moreover, in a faulty condition, it will drain the battery much faster. ))
Good work 👍
those simple cap testers can give incorrect readings if the cap has any resistive leakage or high esr, and as for the cap testing high, DOESNT necessarily mean its bad , could be because its hasnt had power on it for years and deformed, if so it will appear 'leaky' or 'lossy' to one of those testers, try reforming it to max volts first, then discharge, also many caps had wide positive tolerance, i've seen some specified as +80%, -20% !
I guess you could have stopped the video, backed it up to see that the paint spot was facing out...I was going over old video's I watched and seen this one, which I liked.
those 'extra contacts' are clips to take the flat springs of 2 1289 4.5v batteries ...
Mark the caps before taking them out...or take a pic...I have dont this before...and sure everyone else has too...in the video the red mark can be seen, oh and I always check the earphone jack first to see if it is stuck open.......thanks for the video...
cool
I cant watch any more of that.its painful.bodge it a d scarper springs to mind
If the aim was a concours restoration the you would be right, however Jay said right at the start that the aim here was just to get some sound out of it. The alternative is that it ends up in a landfill site. He clearly explained that the cost of a proper repair was uneconomical.
Фазаискатель в руках , позор профессии .