Need Help Repairing Pyle Guitar Amp after short circuit--only hums & pilot lite

[Roark]

That is a most common diode.

You must place a 1N in front of it.

1N4007.

Have you used this seller?:
hstbeto Bellflower,CA https://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=hstbeto&&rt=nc&ftab=AllFeedback
-- who has many  xlnt reviews for:10pcs 1N4007 Rectifier Diode 1A 1000V - $1.60- US Seller - Free Shipping,

listed as MIC Brand,apparently made by:  https://mklec.com , in Ohio 

or who do you recommend?

[Enzo]

Did you look at Mouser?  100% solid trusted seller, as they sell real name brand parts.

https://www.mouser.com/ProductDetail/ON-Semiconductor/1N4007FFG?qs=sGAEpiMZZMtbRapU8LlZD9Yt6EMzPspSFAiKlqofgxo%3d

Those are $1.64 for 10.  Or $5.80 for 100.   And those are from ON Semiconductor, as solid a company as there is making parts.   Looking at the other Mouser offerings in 1N4007, there are some as low as 90 cents for 10.  $3.50 for 100.

Mouser charges for shipping, but if I recall, if you prepay, they don't, is that correct?

[Enzo]

MKLEC doesn't make parts, they are a store selling parts.  I also note at the top of their web page it says they are going out of business in the next few weeks.

[Roark]

Mouser charges for shipping, but if I recall, if you prepay, they don't, is that correct?

Thanks for all the info,Enzo! But Mouser DOES charge for shipping: prepaid it's $9.60,total, for 10 diodes.

Question for DrGonz78 & others : Have you bought 1N4007 Diodes from jlassen36wy?,[EBay company you suggested for the TDA2050 chip]


PS:MIC Brand is Chinese.

[Roark]

To replace my TDA2030 chip I bought a TDA2050  from jlassen36wy = Amp Repair Houston, EBay, :

I just noticed this today on the webpage:
"NOTE: Placing this TDA2050  32watt integrated circuit chip into a 20watt circuit (i.e. replacing a TDA2040) will not increase the power output of your device and may cause instability especially with a 4ohm load."

But my speaker is 4 Ohms. Is this a problem?

[Enzo]

MAY cause...

Find out.

[phatt]

Correct me if I'm way off but I'd hazard a guess that IN4007 is waaaaaay overkill for a circuit that runs at 35Volts???

1N4007 is a 1,000Volt device.
1N4004 (400V) would likely be cheaper and do the same job.

Maybe the factory had no 1N4004's in stock and just used the higher rated devices.
But I could be wrong, lol.
Phil.

[Enzo]

The price difference is negligible, in fact at Mouser, buy one and the 1N4004 cost more.   But they all sell for like 4 to 6 cents each in 100 lot.  Only want 10?  a penny more then.

Since 1000v 1N4007 works everywhere a 1N4001,2,3,4,5,6 works, there is no point in stocking them all.  I have been buying only 1N4007 for decades.  WHy tie up inventory space?  I don't know if Pyle did it that way, but wouldn't surprise me.

[phatt]

Yep fair point but the stores I frequent the stock is often 100pack of 1N4004 and not much else. 
Phil.

[Enzo]

Well, sure, if that is what is available and suits the need, then of course use it.

[Roark]

To replace my TDA30 chip I bought a TDA2050  from jlassen36wy = Amp Repair Houston, EBay.
After ordering I noticed the TDA2050 webpage says:
"NOTE: Placing this TDA2050 32 watt integrated circuit chip into a 20 watt circuit (i.e. replacing a TDA2040) will not increase the power output of your device and may cause instability especially with a 4 Ohm load."

I'm worried I got the wrong chip because My speaker is 4 Ohms!
But My amp is a 30 watt amp & has "Rated Power: 45 watts Peak".

So maybe this chip is OK?

What I don't know is : How many watts is my original TDA2030 chip?..... & Is my circuit 30 watts? 

[TDA2050 is a 32watt chip ; TDA2040 is apparently 20watts? ]

[Enzo]

Putting a "50 watt" IC in the circuit doesn;t make the circuit 50 watts. It just has heftier parts inside.

45 watts peak is marketing rubbish, a meaningless spec.

[DrGonz78]

With the TDA2030A chip running 36v power supply or rather a -/+18v supply it will be max rated at 20 watts as per data sheet. So now you will have the TDA2050 in place that can handle 32 watts at 8 ohms or the claimed 50 watts with 4 ohm load. In those examples though it is with a power supply capable of delivering 50v or -/+25v from the power transformer. Your amp will still have the -/+18v power supply and will have a new chip that is highly overrated to your amp's power supply. Honestly looking at the TDA2030 data sheet I think it's really only putting out 14 watts RMS with a 4 ohm load. I would be surprised if the 4 ohm speaker caused any trouble for TDA2050 chip.

[Roark]

Thanks for the analysis,DrGonz78! ---That's a relief for me!

I was going to follow these instructions:
"Turn the amp on for about 2 seconds then off again. Then put your finger on the plastic part of the chip amp see if it has heated up really quickly. If it is ok for 2 seconds double the time and try again - repeat until you have reached 1 min." "[Amps usually recover if they are load unstable but they will run much hotter than they should so watch for this when you start using the amplifer.]"

[Roark]

With the TDA2030A chip running 36v power supply or rather a -/+18v supply it will be max rated at 20 watts as per data sheet. So now you will have the TDA2050 in place that can handle 32 watts at 8 ohms or the claimed 50 watts with 4 ohm load. In those examples though it is with a power supply capable of delivering 50v or -/+25v from the power transformer. Your amp will still have the -/+18v power supply and will have a new chip that is highly overrated to your amp's power supply. Honestly looking at the TDA2030 data sheet I think it's really only putting out 14 watts RMS with a 4 ohm load. I would be surprised if the 4 ohm speaker caused any trouble for TDA2050 chip.

Here's what jlassen36wy [EBay seller]  said:

"The limitation is the power supply circuit.
As far as thecircuit becoming unstable at 4 ohms, that depends on the circuit design.
The TDA2050does not begin to taper off power at 18 watts.
So, the power supply may become loaded down trying to feed the chip.
It is a design issue, and I have used TDA2050s in all sorts
of TDA2030 and TDA2040 circuits successfully,but I can't guarantee it as a substitute.
[PS: TDA2030 is 18 watts into 4 ohms. TDA2050 is 32 watts into 4 ohms]"

Does that agree with DrGonz78 said above?
DrGonz78 seems to have more information [that I have a -/+18v power supply] & sees no instability problem.