This is my first post in this forum so i really hope I don't violate all rules in the book. I did search to try to understand how to find a suitable replacement for the TDA2030a in my amplifier but since I'm just learning I'm need some guidance of what I can do and what not to do. Here is the case:
I was trying out some different combinations of diodes to get a different character in the diode clipping section. After sitting too long I lost focus and accidentally shorted the diode circuit witch in turn burned the TDA2030a component. So here are some questions:
1. Do I need to replace it with the exact same component or can I use a similar one with the same pinouts (e.g. TDA2050) without changing other circuits on the board? If so, what should I look for?
2. How can I measure if other components were damaged? Don't know what values to look for or where on the PCB to make the measurements
I'd be thankful for any answers that could help me bring my Vox to life
Here is the schematic for the Vox Pathfinder 15r
I was trying out some different combinations of diodes to get a different character in the diode clipping section. After sitting too long I lost focus and accidentally shorted the diode circuit witch in turn burned the TDA2030a component. So here are some questions:
1. Do I need to replace it with the exact same component or can I use a similar one with the same pinouts (e.g. TDA2050) without changing other circuits on the board? If so, what should I look for?
2. How can I measure if other components were damaged? Don't know what values to look for or where on the PCB to make the measurements
I'd be thankful for any answers that could help me bring my Vox to life
Here is the schematic for the Vox Pathfinder 15r
Thank you Harleyjon, I will try with the 2050. Is there a way to measure to see if I have any other faulty component on the board before I solder it on?
The TDA2050 will provide an extra watt or two of clipping headroom at a given supply voltage. Be sure the replacement part is not counterfeit. Ebay is not a good source. In the US, DigiKey and Mouser are known to me to provide authentic parts.
You would have to carefully inspect the amp for damage. Did the TDA2030A show physical damage? Otherwise, how did you conclude it was bad?
You would have to carefully inspect the amp for damage. Did the TDA2030A show physical damage? Otherwise, how did you conclude it was bad?
@johnr66 I just bought my stuff from Elfa here in sweden and I believe they are ok. I draw the conclusion that the tda is burnt from all the heat, smoke, white spot on the heatsink and the crack in the sealing of the IC. If it would still be functioning I need to look up the definition of broken in a dictionary. Anyway I still need some advice on measuring the device before I solder. I'm not that worried that something would go wrong since I was thinking about throwing the amp out long ago, but I want to give it a shot 🙂
You can't measure the new chip, just assume it's good if from a reputable supplier.
Be kind to the PCB when pulling the old one, best is to cut the legs at the "knee", and then pull them straight up one by one, without wiggling, and also using a good solder sucker.
Mount the new TDA20xx , with proper mica and grease if needed, the screw will probably be insulated with a small nylon nipple.
Solder it and pray.
EDIT: just in case, also replace those 2 1N4002 connected from TDA pin 4 (speaker output) to +/-20V rails.
Mark polarity before pulling them.
Be kind to the PCB when pulling the old one, best is to cut the legs at the "knee", and then pull them straight up one by one, without wiggling, and also using a good solder sucker.
Mount the new TDA20xx , with proper mica and grease if needed, the screw will probably be insulated with a small nylon nipple.
Solder it and pray.
EDIT: just in case, also replace those 2 1N4002 connected from TDA pin 4 (speaker output) to +/-20V rails.
Mark polarity before pulling them.
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@JMFahey thanks for your input. I meant that I wanted to measure for expected values on the pcb to look for other faulty components before putting in any new (I see why I was misinterpreted).
Well, since I know nada about making any meaningful measurements I just checked the pcb for any burns, dark spots and old solder crap from previus experiments and then I turned it on with the old amp circuit removed. I wanted to see if there was any heat or smell developing but there was nothing, so I pulled the plug and soldered the TDA2050...
...and
klick...
It worked! so happy
So then I took on the diode clipping section were I screwed up last time. Now I have a switch that lets me choose from symetrical clipping, asymetrical (tube-ish) clipping and diode bypass (witch make it sooo clean 🙂 more like a fender amp. The last thing to do now is to put the reverb connections back, but when I tried yesterday it was humming so much that I decided to disconnect it and leave it for now. Any ideas? (maybe I accidentally put the ins where the outs where supposed to be. It was 4 in the morning so I was not so clever at that point)
By the way I learnt my first noob lesson: Never ever hover with your hand above the AC mains. The current jumped up and kissed me quite good with 240 volts (and the amp was turned off! Forgot to unplug it of course. Yes I'm happy to be alive
Well, since I know nada about making any meaningful measurements I just checked the pcb for any burns, dark spots and old solder crap from previus experiments and then I turned it on with the old amp circuit removed. I wanted to see if there was any heat or smell developing but there was nothing, so I pulled the plug and soldered the TDA2050...
...and
klick...
It worked! so happy
So then I took on the diode clipping section were I screwed up last time. Now I have a switch that lets me choose from symetrical clipping, asymetrical (tube-ish) clipping and diode bypass (witch make it sooo clean 🙂 more like a fender amp. The last thing to do now is to put the reverb connections back, but when I tried yesterday it was humming so much that I decided to disconnect it and leave it for now. Any ideas? (maybe I accidentally put the ins where the outs where supposed to be. It was 4 in the morning so I was not so clever at that point)
By the way I learnt my first noob lesson: Never ever hover with your hand above the AC mains. The current jumped up and kissed me quite good with 240 volts (and the amp was turned off! Forgot to unplug it of course. Yes I'm happy to be alive
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