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Hi , I have a problem concerning my 1972 DR 103 , two out of three times it will blow the main fuse when switched on ... the time when it works the amp will stay on all day and is fine if you don't turn it off , but if you do it's a gamble if it blows again (it usually does) The amp is UK voltage and has a bulgin plug ,voltage and resistance selectors are good .

Now I'm very new to Hiwatts always had marshalls but I know that if it works one in three and sounds good then it can't be anything serious , any ideas?

Thanks .

reverberator wrote:Hi , I have a problem concerning my 1972 DR 103 , two out of three times it will blow the main fuse when switched on ... the time when it works the amp will stay on all day and is fine if you don't turn it off , but if you do it's a gamble if it blows again (it usually does) The amp is UK voltage and has a bulgin plug ,voltage and resistance selectors are good .

Now I'm very new to Hiwatts always had marshalls but I know that if it works one in three and sounds good then it can't be anything serious , any ideas?

Thanks .

Wrong fuse value? You should be using 6,3A fast for mains.

3 amp? oh ok I think the ones I was supplied with are 1 amp ... i'll try it , thanks.

reverberator wrote:3 amp? oh ok I think the ones I was supplied with are 1 amp ... i'll try it , thanks.

No, you should be using 6.3A (six point three amps) for mains

And 3A for HT.

http://hiwatt.org/tech.html

Haha ok , and thats for 245 voltage ?

why has this amp been running 1 amps for years? I dont understand it I just looked at a hiwatt pdf 1974 catalogue that says 5A mains and 3A HT , so yes I've got the wrong fuses .... thanks for the help

Here's another source:

http://hiwatt.org/tech.html

According to this, it should be a 3A for your voltage. Better to try a 3A first and see if it holds up.

Dave

Right ok then ... i'll try 3 amps being as that is what is stated there and if that dosn't work increase to 5A ... i'll try it tomorrow , thanks.

Oh, I'm sorry, I confused UK and USA voltages
You should use 3A

...this conversation reminds me of the old story that ends with; "...that'll hold - until the fire department gets here!"

Dave

3A is fine for mains for a 103 @ 240v.

--mark

Yes , replaced both fuses for 3.15 amp and it's holding up well , switched it on and off several times and no blow.
The output tubes are glowing brighter too , they were slightly dim before . Thanks everyone for your help.