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There is a chip that starts smoking with the 8 legs. I can still see the number YWN3M2NB UTG2822M next to the blue capacitors. Where can I find these please ?
I didn't do anything wrong myself, when the uBITX came home in the mail I heard something rattle. It was the speaker, I'm sure it destroyed the chip
Thanks in advance
Mor
ON3MK??

Just ordered the chips .I hope there are no other things going up in smoke?
73,
OM3MK
Mor

On Sat, Aug 14, 2021 at 06:47 AM, Peter McCracken wrote:

That's the audio amp, LM386T

the UTG2822M is NOT a LM386!
TDA2822M (second source) was problematic on the V3. (did not meet original manufactures SOA)

Mor, what version of the uBITX do you have?? (assume V3) What input voltage were you running?
Might want to drop the voltage to the TDA2822M down to ~9V.

I was one of the lucky ones who purchased a V3 with the problematic IC prior to it being socketed.
After pulling the IC (which really wasn't much of a chore) , I added a socket and replaced with an ST micro IC (15V Vmax).

Rgds,
Gary

Wasnt there a drop-in replacement for the tda2822?
Some pin compatible amp chip from JRC or NRC that could take 16volts?
So no reengineering to use some other amp or adding a regulator for the audio amp required?

I bought the radio from an ham operator I think for sure the? V3 version? green display and two pot buttons on the front plus ptt? phone and key I buy two pieces on Ebay? like Peter say
73 for now and thx for helping me
Mor

Peter, the number quoted has 2822 in it and famous for smoking.

Mor, please check the version on your PCB corner and tell us.
Some boards have different chips.

Raj

Please order TDA2822 type chips. There are JRC equivalents which I prefer NJM2073D.

NTE7155 is another one

Raj

On the chip there stay? YWN3M2NB? ?UTG2822M? ?so did i buy the wrong chip
Thanks in advance
73,
Mor

Your BITX must be V3.. Yes, order TDA2822M

What you ordered will be useful for other projects so its not a waste.



Raj

Are this the good one?


Mor

Looks like a good one Mor, buy a few extra.

Raj


At 15/08/2021, you wrote:

Ordered? 5 pieces, thanks for helping me?
73,
ON3MK?
Mor

I did my order on Ebay,? are the chip on Aliexpress? the same?
I see 10 pieces plus shipping for 5 Euro ,have to wait? for delivery? sep. oktober
Thx in advance 73
ON3MK
Mor?

The ones you ordered will probably work fine, but Ebay vendors can be a gamble.
The TDA2822M in the 8 pin DIP has been discontinued by the original manufacturer
? ?
It was a popular device, and perhaps a dozen different shops are now building clones of it.
The original device was spec'd for operation to 12v, an "absolute max" of 15v beyond which it might be destroyed.
Some clones lowered the "absolute max" on their datasheet to 12v.
And some of those clones, even if they have a datasheet claiming 12v max, would be destroyed if used beyond 8v or so.
Most clones don't have a datasheet.

If I were to buy a replacement part, I'd go with the JRC?NJM2073D as recommended by Raj,
and buy it from a reputable distributor who I know will not be substituting some clone.
Some Ebay sellers go so far as to scrape off the markings of a cheaper low frequency TO220 FET, mark it as a $0.50 IRF510.

Regarding the stock v3 uBitx, they all apparently went out with either FCI or WX branded TDA2822M's.
Very few of the FCI brand parts had troubles, though you could exceed power dissipation limits
if operating at 12v or more, with volume up to full blast, and/or driving into less than 8 ohms.
Some WX brand parts worked fine at 12v, others blew in a puff of smoke at some random moment.
When buying replacement TDA2822M's on the web, there are many other clones beyond FCI and WX that you might get,
some of them have similar issues to the WX, few have a datasheet, almost none claim an absolute max of 15v.

I am not aware of problems with any of the LM386 clones blowing at supply voltages of 12v,
though some have far more distortion than others
? ?
.
Possible fixes for those with the WX brand TDA2822M parts in their v3 uBitx:
? ? Replace with a?NJM2073D or similar known good clone
Hack in an LM386 following the schematic of the v5 or v6 uBitx, a matter of swapping pins around on that DIP-8 part..
? ? Use one of the many LM386 amplifier breakout boards available on the web, tie it into the volume pot wiper.
? ? Reduce the supply voltage into the WX TDA2822M to 6v (instead of the stock 12v) by adding a 3 terminal voltage regulator?
? ? Adding an 8 ohm resistor in series with the output of the TDA2822M is not a bad idea, but the primary issue is the supply voltage.

The TDA2822 was a fine choice for the v3, I was sad to see it dropped on the v4.
The issue was simply one of buying sub-standard parts.?
That can happen with most any electronic part if you are pressing for low cost.

Another v3 issue regarding substandard parts was the provided BNC connector,
some of them were machined out of spec such that the center pin did not make good contact.
The antenna connection was intermittent when the coax was wiggled, subjecting the finals to high SWR..
That does not mean BNC connectors should be avoided, it means you must choose a vendor that sells good parts.

A search for "TDA2822" in this forum will find some very long discussions about all of this when the uBitx came out.
There were a half dozen different theories as to why some failed, it took months to figure out that it was primarily
a problem of the WX brand parts failing when powered from more than around 8v.

Jerry, KE7ER

Mike Woods??ZL1AXG, has a comprehensive writeup of v3 TDA2822 issues here:
? ??/g/BITX20/message/82143
Along with other good stuff on the *BItx* rigs.

Speaking of whom, we haven't heard from Mike for nearly a year now.
He's in my thoughts.
? ??/g/BITX20/message/82143

Jerry, KE7ER

Ok Jerry ,I will keep you informed, I know about the clones and you always have to watch out. But in the end you have to make a decision. Thanks for your detailed explanation
73,
Mor
ON3MK

We had a very long discussion when the TDA2822's failed on v3.

Some were pointing fingers at the momentary short you get when plugging in headphones,
or low impedance speaker loads.? There is some truth to that, the datasheet shows that the part
will overheat if you drive low impedance loads at high volume levels with a high supply voltage.
And most of the clones have a 12v absolute max voltage spec (those few that have a datasheet)
most of us are likely running it with to high a voltage.? (The JRC part is spec'd for 15v absolute max)

But almost all failures were with the WX parts, not the FCI parts.
And I doubt the FCI parts are as good as the original ST parts, or the JRC?NJM2073D.

If worried about failures I suggest any replacement be the Raj's JRC part,
but leave good enough alone if your part works and it isn't a WX.

If still worried, then reduce the supply voltage to that chip to perhaps 6 or 8 volts using a 3 pin linear regulator.
The TDA2822 will be just loafing along, it would be hard to burn it up even with a low impedance load
at max volume level.?

A momentary short at the headphone jack should not be disastrous even at 12v,
as the silicon die won't have time to heat up.? But if you are still worried, add the 8 ohm series resistor.

My v3 still has the original FCI part with no mods.??
Doing just fine.

Jerry, KE7ER