TDA2030A Audio Power Amplifier Question

[RetroComputingGrotto]

My boss always says "the only stupid question is the one not asked" so at the risk of asking a stupid/obvious question I'm going to one any way...

I've got a pair of speakers with an amp built in to them in for repair and on inspection I can see the TDA2030A amplifier ICs have blown (so I've ordered some spares which should arrive soon):



My quesion is with regards to the white paste you can see on the TDA2030A and heatsink, I'm assuming this is just some thermal paste and if so is it a special kind or will the grey thermal compound that I have in the store cupboard that is used for computer CPUs be OK?

[redwire]

It's (silicone) thermal grease for better heat transfer from the IC to the heatsink. You can use CPU grease, the original has nothing special here. That white stuff is messy silicone and cleanup with IPA and Q-tips.
Note the tab on a TDA2030 has power on it (-V_s) so it typically is insulated (electrically) from the heatsink. I don't see you having that (insulator and bushing) so the heatsink must have juice on it which is OK but can be a rude surprise.
Newer IC's like LM1875 have the same pinout and can be dropped in as well. It has better protection if you keep roasting the 2030. The TDA2040, 2050 could also work.

[stj]

one shatterd chip happens,
2 is a bit of a coincidence.
check the circuit and make sure you dont have shorted output/damping capacitors or some fault causing the chips to be driven by AC.

[RetroComputingGrotto]

It's (silicone) thermal grease for better heat transfer from the IC to the heatsink. You can use CPU grease, the original has nothing special here. That white stuff is messy silicone and cleanup with IPA and Q-tips.
Note the tab on a TDA2030 has power on it (-V_s) so it typically is insulated (electrically) from the heatsink. I don't see you having that (insulator and bushing) so the heatsink must have juice on it which is OK but can be a rude surprise.
Newer IC's like LM1875 have the same pinout and can be dropped in as well. It has better protection if you keep roasting the 2030. The TDA2040, 2050 could also work.

Thanks I'll bear that in mind for the future (I've added it to my repairs notes I keep in Microsoft OneNote).

Is there any specifics I should look out for when purchaseing some white thermal grease or is any one from an electronics repair distributor (like the one in this link) OK?

https://cpc.farnell.com/kontakt-chem...4?st=silicobne

one shatterd chip happens,
2 is a bit of a coincidence.
check the circuit and make sure you dont have shorted output/damping capacitors or some fault causing the chips to be driven by AC.

The capacitors were not very happy so I have replaced them already! They were both very swollen. Working in a school they keep these speakers on 24/7 as if they get turned off our helpdesk gets inundated with calls saying there is no sound in all the rooms as they are unable to operate an on/off button or switch. How a Teacher manages to operate their light switches, TV and microwave or air fryer at home is a mystery as they all have the same on/off button and symbol on them as the equipment at work!!

[RetroComputingGrotto]

I've just had a look on CPC's website and they sell 2 different LM1875 ampliers:

https://cpc.farnell.com/texas-instru...?st=M18%20BH-0
https://cpc.farnell.com/texas-instru...8489?st=lm1875


The 25W one is cheaper than the 20W one by nearly 50% - I believe the TDA2030 is 14W so are either of the above a good replacement or would the 20W one which is closer to 14W be the better choice out of the two?

[stj]

buy the cheap one,
the only difference in part numbers is the code for lead-free packaged.

[momaka]

The above 2 links are not working for me - I get an "Access Denied" error. IIRC, this is the 2nd time I get this problem now with farnell. Looks like their website uses a shitty design where if links are viewed from a different country, it just doesn't work.
With that said, instead of links, can you post the manufacturer part numbers instead? (These are usually the same regardless if looking up on farnell or Mouser or Digikey, so that way we can see what you are seeing.) As for the output power to the speakers, that is usually limited by the output voltage (and sometimes power supply power output rating.) If these computer speakers use a plain ol' AC line transformer instead of an SMPS, there's a good chance the transformer voltage will drop quite a bit under high power demand, thus limiting the output power that can go into the speakers even further. With that said, there may not be much of a difference whether your amp IC is capable of 14, 20, or 25 Watts. They are all class AB, so the efficiency will always be the same... thus the heat output will be the same too.

Speaking of heat output (and heatsinks)... you can use any thermal compound to couple the new IC to the heatsink. CPU/GPU "gray" thermal compound is probably (usually) superior to the regular white silicone thermal compound. But in this application, it doesn't matter at all, because the average dissipated power by the amp IC will be relatively low. So any thermal compound will do. In fact, if the old IC wasn't physically broken like you show in the pictures, then you could have even re-used the thermal compound from the old IC, provided that it wasn't dry / chalky yet. I do that all the time when I'm lazy or "temporarily" fixing stuff (with some of those "temporary" fixes being years old now, LOL ).

[RetroComputingGrotto]

instead of links, can you post the manufacturer part numbers instead?

Here you go!

[redwire]

one shatterd chip happens,
2 is a bit of a coincidence.
check the circuit and make sure you dont have shorted output/damping capacitors or some fault causing the chips to be driven by AC.

It might be running the IC's in bridge mode BTL for the pair. Is this a stereo on mono thing. I would expect the speaker got roasted when the IC shorted. Kids cranking up music can do it.

I would get a pair of the best price LM1875 the noPb ones.

[RetroComputingGrotto]

Cheers guys!

[momaka]

OK, as we suspected, there's not much difference between the two, other than one being Pb-free. So just get the cheapest one.
BTW, it might be worth investigating the output voltage of the power supply in the speakers. Perhaps it was close to the absolute maximum rating limit of the IC, and that's one possibility why both may have blown.

[RetroComputingGrotto]

Both ICs were replaced (along with the 2 large powerline capacitors which were swollen) and the speakers are now working coreectly.


I have another set of speakers in for repair (like busses they keep on coming) and they have similarly numbers AMP ICs:





The speakers in question are Behringer which basically make a decent pair of speakers at a very good (low) price so even the same model of speakers can have different cable connectors in them for example depending on what the manufacturer could get the cheapest!


I'm going to assume the D2030A and V2030D are pretty much the same thing? Asumming this is correct, are the TDA2030A ICs I have also the same thing as they are all 2030 Amps - in other words, can I replace a suspect D2030A or V2030D with a TDA2030A?

[stj]

same thing, just a tacky rebrand.
those caps with the 4 point diamond are absolute shit btw.
replace them with panasonic low esr like FR or some rubycon ZL and they will sound better

[RetroComputingGrotto]

same thing, just a tacky rebrand.
those caps with the 4 point diamond are absolute shit btw.
replace them with panasonic low esr like FR or some rubycon ZL and they will sound better

Thanks that's what I was hoping. Both replaced and after PAT testing them, the speakers are now back in a classroom ready to be used.

Thanks also for the feedback on the capacitors, I do try and by Panasonic or Rubycon when available but I'm limited to places like CPC or RS Components and their minimum order cost before free delivery etc. - feedback like this is genuinely always appreciated.

[stj]

you dont pat test electronics - it can damage them.
you only inspect the cabling and any earth bonding to the chassis.

i have a thread or atleast a bunch of posts here about the PAT scam and how it is mis-interpreted.

[stj]

a quick follow-up.
if you have a transformer with an output of 18v for an amp - just an example.
and you hit it with 500v the transformer will hit the electronics with about 40v
use the full 2kv and you can use your imagination.

if the device has surge supressors in it they will break down and stop your tester or take partial damage and short out later on.