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Power Supply Filter Caps
Here are five very old paper style filter caps. These caps have been known to leak with age and even to explode. This can cause a chain of problems maybe even taking out other components with them when they go. Also due to the high DC voltages (sometimes as high as 460VDC) that travel on these, keeping them new and fresh is a good idea. |
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The Preamp Side of the Circuit Board
Notice the old paper decoupling caps - also a candidate for replacement. They too are electrolytic and fail with age. ON the other hand the Mallory Blue coupling caps are in good shape and since I'm trying to maintain as much original tone in this restoration - I'll keep them around.
The chocolate drop cap on the right is a tone robber according to one of my amp guru's so I popped in an orange drop replacement - it can't hurt and I bought plenty of them. |
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Reverb, Tremolo, Phase Inverter, and Power amp side
More things to replace. I added a 1Meg carbon comp resistor to the input jacks - there were carbon film ones someone had wired in. One of the gurus I read swore by these carbon comps in this one spot - a tone thing, besides they are what would have been there originally anyway. The flame resistant carbon film resistors which were already in the amp were left alone in other areas since they are the standard replacement for carbon comps which can catch fire. |
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The Tranny Side and Bias Circuit
Only replacements here will be a new 3 wire 110V plug with earth ground - someone already replaced the bias cap otherwise I'd do it. The toggle switches are old, I like new AC switches and the high voltage standby switches can get noisey after years of use. I noticed the filament resistors on the power tubes were missing - I will add them only because they are part of the schematic. Someone(s) had definately worked on this amp in the past - notice the white filament wiring. |
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New Sprague Filter Caps
Notice how clean the chassis looks now! Please NOTE POLARITY when changing any electrolytic caps out. Otherwise you'll experience the 4th of July early. |
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The Remodeled board - right side
New power cord, and caps - the orange drop caps were installed because of some bad solder joints and possible deterioration of the blue Mallory caps I found in that area.
All of the old paper decoupling caps are replaced with new Sprague Atoms - a fraction of the size of the old ones. Some new resistors also added by a previous repair job.
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Left Side
Here I replaced an ailing optcoupler on the vibrato, and the associated disc caps just for good measure. This brought things really to life. I also did a Fender Approved repair on the tremolo circuit to kill the "ticking" sound when its on but not in use. |
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Front Shot of the Amp with all the fixes and trimmings.
Notice the cleaned up reverb bag - Inside I added a new 6 spring reverb tank (which I may replace - too much reverb).
All tubes have been replaced with NOS US and British manufactured tubes. GE, Mullard, JAN RCA, & Sylvania |
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