Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Saransk on November 15, 2019, 03:21:11 pm
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If you look at the Ibanez TSA15 schematic that is "floating around" on the various forums, The primary fuse (F1) in the AC line is listed as T6.25AL for 120V - for us old guys that is 6.25 Amps slow-blow.
The markings on the circuit board, for the same fuse (F1) is T1.6AL (????) which is about 1/4 of the schematic value.
Less than 2 amps for a primary fuse seems to be a bit anemic at best.
Has anyone determined what is the correct value - or who might know.
Unit was sold because it blows the Primary fuse when the B+ is connected even without the tubes.
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ha, someone just asked a week ago but I can't find the thread :dontknow:
the best answer, a 15W amp don't use 6A fuses
my answer, experiment, quit if it keeps blowing at 3A and troubleshoot
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1A line should be more than plenty.
Rather than kill fuses one by one, use a Lamp Limiter. A 100W incandescent lamp in series should not show visible glow. Sounds like it will. Disconnect all the PT secondary leads P4-P11 (do NOT let them short to each other). Is it OK now?
However ALL the secondary windings ARE fused. Are they the right fuses?? If someone cleverly replaced the 0.5A with a 15A, suspect the HV rectifier and capacitors have gone short.
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Please keep all inquiries about this amp in one thread. You have already been given an answer in your previous thread.