[AMPS] Caps on Dentron ML-2500

[measures]

>
>I have am going thru the process of reforming the PS caps in a ML-2500 amp.
>I am using a Eico 950B resistance capacitance comparator bridge for a
>variable PS and am measuring the ma by monitoring the voltage across a 20K
>resistor in series with the cap.  The general technique is to rise the
>supply voltage until I see about 1 ma of current (20 volts across the 20K
>resistor. .  I let the voltage set until the indicated current quits
>dropping and then rise the voltage until I see about 1 ma of current again
>and then repeat the cycle.
>
>This schematic on this amp shows 6 FP electrolytics 150 mf a @450 Vdc.  The
>amp has 3 spragues that match the skematic and 3 CD caps that are mutli
>section that are hooked in parallel.  So far I have reformed the 3 spragues
>which had a leakage of about .5 ma at 450 Vdc.  I will have to see how the
>CDs look.
>
>This subject has be covered before, but what is a good leakage limit guide
>line for reuse or replace in this application and if replacement is
>warranted, 

I replace anything that has more than 250uA of leakeage at the rated V at 
room temp.  .  I replace anything with white deposits around the safety 
vent. 

>what is a good source for replacement caps?
>
Mouser, Digikey.  I would go for the extra cost of 105 deg.  C units and 
choose more than 150MF.  . If the WV is close to the rating, I would add 
one (fwb) or two (fwd) more caps.  

cheers, Jim

measuring the values of the old equalizer resistors might be fun.  

-  Rich..., 805.386.3734, www.vcnet.com/measures.  


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