1875 will take supplies from +/- 7.5 to about +/- 30 Volts, so the best candidate for drop in replacement.
2030A may just be available from ST if you are lucky to find NOS.
You did measure DC and not AC volts, right?
2030A may just be available from ST if you are lucky to find NOS.
You did measure DC and not AC volts, right?
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It probably is really as it will be a pretty generic type of circuit used.
And that's me done for today 🙂
And that's me done for today 🙂
I did measure DC volts, yes.
What do "ST" and "NOS" mean?
Here are pictures of the chip and it surrounding capacitors:
https://imgur.com/a/DjHtOxQ
Also, the original pics in case you missed them: Imgur: The magic of the Internet
I am working on de-soldering it, but will probably need to do that later today. No braid on hand, so will need to figure something out 🙂
Thanks for all the help, by the way!
Okay, I desoldered the chip, and (assuming I got the pin numbering right), the DC voltage across pins 3 & 5 is 35.6
So that would mean a 2050, from what you said above?
From the spec sheet Mooly provided, I only see it mentioning supply voltage +/- 25v, though. But I am not great with electronics, so could be misinterpreting something. It also says "High Operating Supply Voltage (50V)" near the top of the page...
Looks like I can get a package of 10 for about $8.00, so that's nice.
If you have the amp chip out, look at it carefully through a magnifying glass. If you can see any hairline crack in the case it is definitely blown. Note: not seeing a crack doesn't mean it is OK, but a crack is a definitive sign of failure.
No hairline crack, but thank you for making me look closer - I see now that it has black-on-black text which says "TDA2030A" So that is nice to have cleared up.
Is it better to order the exact same part?
Or would getting a 2050 be less likely to break in the future?
I'm not sure what's safe w.r.t. swapping different components with different input/output ratings...
Is it better to order the exact same part?
Or would getting a 2050 be less likely to break in the future?
I'm not sure what's safe w.r.t. swapping different components with different input/output ratings...
You can usually drop in a higher rated component with the same pin-outs, so the 2050 would be a good choice and less likely to blow. I don't know if that's a discontinued part, NOS = new old stock, i.e. bits from ages ago that were never used. The LM1875 might be even more robust and has the same pin-out. I don't have experience with any of these chips.
Checking some youtube videos on verifying if the 2030 is working (eg: this one), the voltage drops on the pins all seem reasonable. But maybe that's not telling the full story, given the overheating that was apparent earlier.
I ordered a replacement anyway, so will see how that goes when it arrives.
I ordered a replacement anyway, so will see how that goes when it arrives.
35.6 is too high for the 2030, it is safe till about 30 volts.
Better to replace with 2050, which can take 50 volts, or the 1875, which can take 60.
+/- 25 V is relative to zero, so it is +25 to zero, and -25 to zero, or 50 if you measure from +25 to -25...zero is ground.
1875 has the widest working voltage so the best choice for replacement, at lower voltages it has the same performance as 2030, and at higher voltages it is used either / or with 2050.
Check the supply diodes too, and the supply to the smaller speakers, that could be a problem waiting to happen too.
Better change those too if needed, the voltage is too high for a 2030, which I suspect is used to drive the smaller speakers too.
Or check the supply volts and the chip spec for that side too.
ST is SGS Thompson, a big maker of semiconductors, mostly generic, in that they are rarely the original developers of the parts they make, they start making legal copies after the original maker stops making them. Sometimes they make parts to order, like ARM controllers for specific applications.
Good quality, but in their range the last one produced was the TDA 2030A, and that was long back.
After changing the chip, check the DC volts again on all speaker outputs.
Chinese copies of both are 20 Rupees here.
And get a solder sucker too, useful for removing solder during repairs.
Better to replace with 2050, which can take 50 volts, or the 1875, which can take 60.
+/- 25 V is relative to zero, so it is +25 to zero, and -25 to zero, or 50 if you measure from +25 to -25...zero is ground.
1875 has the widest working voltage so the best choice for replacement, at lower voltages it has the same performance as 2030, and at higher voltages it is used either / or with 2050.
Check the supply diodes too, and the supply to the smaller speakers, that could be a problem waiting to happen too.
Better change those too if needed, the voltage is too high for a 2030, which I suspect is used to drive the smaller speakers too.
Or check the supply volts and the chip spec for that side too.
ST is SGS Thompson, a big maker of semiconductors, mostly generic, in that they are rarely the original developers of the parts they make, they start making legal copies after the original maker stops making them. Sometimes they make parts to order, like ARM controllers for specific applications.
Good quality, but in their range the last one produced was the TDA 2030A, and that was long back.
After changing the chip, check the DC volts again on all speaker outputs.
Chinese copies of both are 20 Rupees here.
And get a solder sucker too, useful for removing solder during repairs.
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What should I check for here? Just make sure the diodes are not open-circuit in both directions?
I'm not actually sure which components go to the small speakers. There's a "tie fighter" shape heat sink on some other chip; not sure if that's related (you can see it in the pics).
I can work on tracing the circuitry though...
Sorry, I'm pretty novice with this stuff. Thank you for the info though.
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Yes, check for open and shorted diodes, both ways.
On diode test, the readings should be close to each other, if not, a diode is weak. It is usually the 2k resistance range on digital meters.
The smaller speakers would be connected to another chip amp, possibly another 2030, you need to check that too, as the supply is the same, to both amp sections, the lower voltage is for the Bluetooth.
On diode test, the readings should be close to each other, if not, a diode is weak. It is usually the 2k resistance range on digital meters.
The smaller speakers would be connected to another chip amp, possibly another 2030, you need to check that too, as the supply is the same, to both amp sections, the lower voltage is for the Bluetooth.
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The transformer can be upgraded, it is really small, a different solution is to use a laptop brick, and a 7805 to supply the Bluetooth...see if there is a three pin device on a small heat sink somewhere.
7805 is a 5 Volt regulator.
7805 is a 5 Volt regulator.
At that price, GUARANTEED fake.
Buy ONE 1875 from a reputed supplier instead.
Where do you actually live?
City/Country please.
I think ST TDA2050 is NOS, and the quote here was US $3, and sold out.
Choice is for 1875, as the only original one still made.
Or go for Wuxi, Chinese, they make both 2030A and 1875.
UTC Taiwan makes the 2030 / 2050, reputable company, possibly licensed.
But 80 cents of which currency?
1875 is above US $1 in bulk quantities...
Choice is for 1875, as the only original one still made.
Or go for Wuxi, Chinese, they make both 2030A and 1875.
UTC Taiwan makes the 2030 / 2050, reputable company, possibly licensed.
But 80 cents of which currency?
1875 is above US $1 in bulk quantities...
35.6V across pins 3 and 5 means it is running on approx -/+18 volts which is fine and is actually the nominal supply voltage used in the data sheet test circuits. It (TDA2030) is good to 44v (-/+22 volts) The very small transformer means the supply voltage will fall anyway under load and is a kind of built in safeguard in these kind of designs.
I would get a new TDA2030A from a reputable authorized supplier. If everything was cold with the chip removed then there won't be any other failed semiconductors. If a diode had failed in the power supply then it would be hot and the big caps would be hot as well.
Visually check the big caps to make sure they are not split or bulging at the top.
Chip failure is a classic fault and we used to be replacing these things daily in our work in a busy service department.
Before replacing the chip make sure that there is no residual high voltage on the big caps. A volt or two is OK, anything more then discharge them first.
Edit... make sure you understand how the chip is mounted with its insulating washer and bush. The tab of the chip must be electrically isolated from the heatsink. If the washer is damaged then get a new mounting kit. If it is a mica washer then I would replace it anyway using a greaseless type.
My Philips amps run on a 0-14-28 supply, 14 for pre amp, tuner, cassette...and 28 for the power amps.
The practical issue is getting a reliable 2030 wherever he is, so the LM1875 will be the right choice for a proper replacement.
He can take a chance with TDA series chips, most likely fake.
The practical issue is getting a reliable 2030 wherever he is, so the LM1875 will be the right choice for a proper replacement.
He can take a chance with TDA series chips, most likely fake.