Hello,
I am currently working on swapping over the voltage from 117V to 220V in my mesa Boogie 20/20 Power Amp. I am going to make a subsequent post once it is done describing the value of the Varistor that needs to be used, to save others who perform this conversion from suffering Mesa's ridiculous price for the part (it was 10 times the price in Australia!).
Anyways, while I had the lid off I noticed a number of resistors have started to burn out - just got too hot I guess.
The ones I refer to are the 10 lot of 330ohm resistors on the far right of the circuit board with the large blue capacitors. These are wired in series for anyone who is interested.
I am wondering what power rating these are. I read on another forum that these may be 0.5 watt resistors. But I went and purchased a bunch of 330 ohm 0.5 watt resistors and they appear to be half the size of the originals.
Are they 1W perhaps? Or, as they are old (amp is circa 1994) perhaps they were made with a different material and were larger than today's equivilants?
I am a bit worried about heat dissipation in the circuit (they have almost burnt up once before, which is why they need replacing). I am going to solder the replacements higher off the board to aid in airflow.
Grateful for any insights of advice.
VidarAus
I am currently working on swapping over the voltage from 117V to 220V in my mesa Boogie 20/20 Power Amp. I am going to make a subsequent post once it is done describing the value of the Varistor that needs to be used, to save others who perform this conversion from suffering Mesa's ridiculous price for the part (it was 10 times the price in Australia!).
Anyways, while I had the lid off I noticed a number of resistors have started to burn out - just got too hot I guess.
The ones I refer to are the 10 lot of 330ohm resistors on the far right of the circuit board with the large blue capacitors. These are wired in series for anyone who is interested.
I am wondering what power rating these are. I read on another forum that these may be 0.5 watt resistors. But I went and purchased a bunch of 330 ohm 0.5 watt resistors and they appear to be half the size of the originals.
Are they 1W perhaps? Or, as they are old (amp is circa 1994) perhaps they were made with a different material and were larger than today's equivilants?
I am a bit worried about heat dissipation in the circuit (they have almost burnt up once before, which is why they need replacing). I am going to solder the replacements higher off the board to aid in airflow.
Grateful for any insights of advice.
VidarAus
