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Hoffman Amps Forum image Author Topic: Anyone ever seen this? Replace with standard?  (Read 2471 times)

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Offline MrPink

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Anyone ever seen this? Replace with standard?
« on: April 09, 2024, 03:57:13 pm »
Seems like

well i guess it is

Offline acheld

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Re: Anyone ever seen this? Replace with standard?
« Reply #1 on: April 09, 2024, 05:16:57 pm »
Cool.  I have not seen and old one like that.   If it is red violet black gold, you'd replace it with a 27 ohm resistor + an appropriately sized fuse in series.

Offline MrPink

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Re: Anyone ever seen this? Replace with standard?
« Reply #2 on: April 09, 2024, 05:46:29 pm »
they're in between power switch and PT
makes me wonder
and its red red black gold, so 22ohm, fuse beeing 1/8 A rated. found 20ohm replacement online so i'll go with that

Offline Beezerboy

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Re: Anyone ever seen this? Replace with standard?
« Reply #3 on: April 10, 2024, 06:37:32 pm »
looks like rrb to me, so 22.  both yer fuses look to be blown... why?  you are going to drop the resistance 10%, also consider that your amp may have been designed to run on 110.... 115.... maybe 117 VAC. that may not end well. I would be more inclined to add a resistor to the fuse holder. maybe even one that will bring the voltage back to the original range

Offline MrPink

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Re: Anyone ever seen this? Replace with standard?
« Reply #4 on: April 11, 2024, 05:32:00 am »
both yer fuses look to be blown... why?

It's two PT's in one, and one of them is broken/bulged. they're for 110 and 230v. tryin to get that thing running by getting the broken one out of circuit but maybe I'll leave it as well cause it's not worth the time... don't know yet
It's a crate TDP by the way

Offline kagliostro

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Re: Anyone ever seen this? Replace with standard?
« Reply #5 on: April 15, 2024, 02:46:29 pm »
I asked in an Italian forum

A friend told me they were "extra slow blow"

They will blow in two different manners due to different problem

Manner one, a very large current over the spec, the wire will blow

Manner two, a small larger current only a bit over the spec, after some time the heat developed on the resistor will melt the alloy that joined the resistor to the spring, an alloy designed with a specific melting temperature, the function of the spring is to help the wire and the resistor to be separated from the other side of the fuse connection

Franco
« Last Edit: April 15, 2024, 02:49:28 pm by kagliostro »
The world is a nice place if there is health and there are friends

Offline MrPink

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Re: Anyone ever seen this? Replace with standard?
« Reply #6 on: April 15, 2024, 05:31:34 pm »
Thx!

in case anyone else searches this fuse type: 0313.150MXP Littelfuse is the closest/only replacement i could find, they have different impedances in that 0313 line but currently 17 weeks till delivery
guess someone switched that thing from 230v to 110 v while plugged in and running and blew the very small pt in it

it's a pitty i dont have a schematic or any information on what that pt output was supposed to be
« Last Edit: April 15, 2024, 05:33:53 pm by MrPink »

 


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