fuse of vintage JBL

[pyonc]

Hi friends,

I need a new fuse for JBL SG520 preamp. According to the manual, it says "a Slo-Blo fuse. A 3/10 AMP. fuse is required for 110-120 volt operation.' I'm not familiar with this kind of fuse. On ebay I see lots of fuses that look like this one, but I can't find the exact match. I appreciate it very much if you can let me know (hopefully a picture), or send me a link to any auction site on the right slo-blo fuse.

[hjames]

Hi friends,

I need a new fuse for JBL SG520 preamp. According to the manual, it says "a Slo-Blo fuse. A 3/10 AMP. fuse is required for 110-120 volt operation.' I'm not familiar with this kind of fuse. On ebay I see lots of fuses that look like this one, but I can't find the exact match. I appreciate it very much if you can let me know (hopefully a picture), or send me a link to any auction site on the right slo-blo fuse.

You do need to know what the actual fuse is, not a generic description like you listed.

Size (length) is going to be critical to actually fit the fuseholder ...
Should I gather you have the original fuse in hand??
If its a Buss brand fuse, (or something like that)
it should have a part number stamped on one of the silvery bands ...
3AG or something similar ...


Try an actual electronics outfitter like Capital Electronics in Gaithersburg, MD -
instead of the auction site ...
You should be able to get a box of Slow Blow fuses for $5 or so ...
https://www.capitaltristate.com/
or maybe someone like
https://www.suburban-electronics.com/





http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-SG520.pdf

On page 22, it says - 4Amp 120 volts slo blo
on page 28, it says 3/10 Amp slo blo

[pyonc]

You do need to know what the actual fuse is, not a generic description like you listed.

Size (length) is going to be critical to actually fit the fuseholder ...
Should I gather you have the original fuse in hand??
If its a Buss brand fuse, (or something like that)
it should have a part number stamped on one of the silvery bands ...
3AG or something similar ...


Try an actual electronics outfitter like Capital Electronics in Gaithersburg, MD -
instead of the auction site ...
You should be able to get a box of Slow Blow fuses for $5 or so ...
https://www.capitaltristate.com/
or maybe someone like
https://www.suburban-electronics.com/





http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-SG520.pdf

On page 22, it says - 4Amp 120 volts slo blo
on page 28, it says 3/10 Amp slo blo (3 to 10 amps?)


Thanks so much for your useful information!:applaud:
I think I have to take the old fuse out first to check it as you suggested.
Also, thanks for the info on Capital Electronics in my area, too.

[pyonc]

By the way, what is this 3/10 AMP. here? Is it any slo-blo fuse rating from 3 ampere fuse to 10 ampere fuse?
In other words, exceeding 3 ampere fuse rating but less than 10 ampere fuse rating? Just confused...

[Earl K]

NO!

( 3/10 ) is the same as ( 3 divided by 10 ) is the same as ( 3 over 10 ) which is just another way of saying the previous 2.

= 0.3 amps

Take the fuse out and measure it, there are a few sizes present in electronics equipment.

Hopefully it's 1.25"Long x .25"Diameter

:p

[Baron030]

Hi Pyonc
Looking through the manual, your amp has two fuses. Since, you are living in the state of Maryland. I can assume that you are running this amp with 115 volts. So, the 3/10AMP fuse is referring to 0.3 amps, as in 3 tenths of one amp. My guess is that it is a 3AG sized fuse. And 3AG refers to the physical size of the fuse and not it current rating. The other fuse is for the switched outlets and is most likely a 3AG – 2 amp Slo-Blo fuse.

82385

Best of luck
Baron030:)

[pyonc]

NO!

( 3/10 ) is the same as ( 3 divided by 10 ) is the same as ( 3 over 10 ) which is just another way of saying the previous 2.

= 0.3 amps

Take the fuse out and measure it, there are a few sizes present in electronics equipment.

Hopefully it's 1.25"Long x .25"Diameter

:p

Thanks so much! :applaud: This is the way I learn from JBL guru like you.

[pyonc]

Hi Pyonc
Looking through the manual, your amp has two fuses. Since, you are living in the state of Maryland. I can assume that you are running this amp with 115 volts. So, the 3/10AMP fuse is referring to 0.3 amps, as in 3 tenths of one amp. My guess is that it is a 3AG sized fuse. And 3AG refers to the physical size of the fuse and not it current rating. The other fuse is for the switched outlets and is most likely a 3AG – 2 amp Slo-Blo fuse.

82385

Best of luck
Baron030:)
Yes, that slo-blo fuse, 3/10 amp. (as attached in the pic). And there is another fuse 1 amp fast blow (second pic) for a different purpose. Thanks so much for your valuable tip, JBL guru! :applaud:

[pyonc]

Today I put in the right fuse with correct rating (3/10AMP), but still it doesn't power up.
Clearly there is another issue. What could it be? Any idea?
Before I take it to the tech shop nearby, I'd like to ask for your comment.
Thanks a lot.

[grumpy]

Personally, I would start with power supplies and related stuff, switches, and relays (if any).
This is an old piece of gear, so there could be many issues, but if there is no power... (or the power lamp is burned out), it’s a good starting point. Sounds like a job for the test bench.

[pyonc]

Personally, I would start with power supplies and related stuff, switches, and relays (if any).
This is an old piece of gear, so there could be many issues, but if there is no power... (or the power lamp is burned out), it’s a good starting point. Sounds like a job for the test bench.

Thanks for your feedback, grumpy.
It's in like mint condition, though.
Let me get back when I get the report from the tech.