Hiwatt DR103 1974 fuse question

DR103, DR103OL, DR504, DR504OL, DR103S (Gilmour), CP103 (Townshend), Lead 30, Lead 50, Lead 100, DR201, DR405, SA112, SA212, SA412, SE4121, SE4122, SE4123

Hiwatt DR103 1974 fuse question

Postby onosnd on Wed May 17, 2017 4:32 pm

Hi,

I blew a HT fuse of my while ago acquired Hiwatt DR103 (Hylight era)
I keep reading that HT should have a 3,15A fuse. My chassis has a marking above the HT fuse slot that says 1AT.
Also the fuse inside indeed was 1A. I wonder what could be the reason behind all this?

All the help is appreciated.

Thanks!
onosnd
Peasant
 
Posts: 5
Joined: Sat Nov 28, 2015 6:36 pm

Re: Hiwatt DR103 1974 fuse question

Postby pdf64 on Wed May 17, 2017 4:49 pm

onosnd wrote:...I keep reading that HT should have a 3,15A fuse. My chassis has a marking above the HT fuse slot that says 1AT.
Also the fuse inside indeed was 1A. I wonder what could be the reason behind all this?...

I think you may be reading bad info (or mis-interpreting good info); where did you see it?
It's generally best to follow the manufacturer's instructions, unless there's a good solid reason not to.
>3A seems way more than the HT can sustain without something being damaged.

Hopefully the fuse just blew in response to a bad tube; treat all the power tubes that were in it as suspect, and replace the fuse with a 1AT (T = time delay = slo-blo).
If you were very unlucky a bad tube may have blown its screen grid resistor, or the fuse blew for a non-tube fault, in which case the amp will sound weak / bad / won't work. In which case a tech's assistance will be needed.
Note that it's a good idea to check that the power tubes are idling at a reasonable plate dissipation.
My band:-http://www.youtube.com/user/RedwingBand
pdf64
Knight
 
Posts: 1243
Joined: Thu Dec 14, 2006 9:55 am
Location: Staffordshire UK

Re: Hiwatt DR103 1974 fuse question

Postby onosnd on Wed May 17, 2017 5:13 pm

pdf64 wrote:
onosnd wrote:...I keep reading that HT should have a 3,15A fuse. My chassis has a marking above the HT fuse slot that says 1AT.
Also the fuse inside indeed was 1A. I wonder what could be the reason behind all this?...

I think you may be reading bad info (or mis-interpreting good info); where did you see it?
It's generally best to follow the manufacturer's instructions, unless there's a good solid reason not to.
>3A seems way more than the HT can sustain without something being damaged.

Hopefully the fuse just blew in response to a bad tube; treat all the power tubes that were in it as suspect, and replace the fuse with a 1AT (T = time delay = slo-blo).
If you were very unlucky a bad tube may have blown its screen grid resistor, or the fuse blew for a non-tube fault, in which case the amp will sound weak / bad / won't work. In which case a tech's assistance will be needed.
Note that it's a good idea to check that the power tubes are idling at a reasonable plate dissipation.



Thanks for claryfying. I think I mis-interpreted some info. I'm not very technical with all this stuff :roll:
I did found a replacement 1A fuse and changed it. Now it works as before. I'l have to monitor it.. if it does it again, I'll take it to a tech.
Thanks.
onosnd
Peasant
 
Posts: 5
Joined: Sat Nov 28, 2015 6:36 pm

Re: Hiwatt DR103 1974 fuse question

Postby Mr. Foxen on Wed May 17, 2017 11:09 pm

3.15a is probably the mains.
New music: https://warriorpope.bandcamp.com/album/anchorite
Gear tinkering blog: http://ampstack.wordpress.com/
Made a Facebook page for my ampguts stuff. Feel free to come post amp guts and rig shots: https://www.facebook.com/pages/Ampstack/351966881575839
Mr. Foxen
Squire
 
Posts: 792
Joined: Fri Aug 13, 2010 9:37 am


Return to Hiwatt

Who is online

Users browsing this forum: No registered users and 3 guests