Chinese Picofarad Meter for Cheap

[The New Steve H]

Also found good prices on big metal film resistors. Are they any good? I do not know. Bought some, though. In fact, way too many. I have a tendency to fry the 4.7k resistor in my 5f6a, so I figured a 3W job might survive longer.

Before anyone asks, the frying happens when I turn the amp on without remembering to remove the lead I use to suck the stored electricity out of it.

[selloutrr]

Also found good prices on big metal film resistors. Are they any good? I do not know. Bought some, though. In fact, way too many. I have a tendency to fry the 4.7k resistor in my 5f6a, so I figured a 3W job might survive longer.

Before anyone asks, the frying happens when I turn the amp on without remembering to remove the lead I use to suck the stored electricity out of it.

funny! The 3W might last longer.. just long enough to burn out the lower wattage components around it

[Zippy]

Before anyone asks, the frying happens when I turn the amp on without remembering to remove the lead I use to suck the stored electricity out of it.

Try hanging a flag or a wrist lanyard to the shorting probe. Better to remember to remove it than try to design for leaving it attached.

[The New Steve H]

Just being realistic here.

[dartanion]

http://www.tubesandmore.com/

Digital Capacitance Meter
Nine ranges give precision readings from 0.1 pF to 20,000 µF. Can be used to check virtually all capacitors for tolerance value, selecting matched sets, etc.

0.1 pf to 20,000 µF, 9 ranges
Over range indicator
0.5% basic accuracy>
Tilt stand
3-1/2 digit LCD, 1"H x 2-1/4" W
1.5" x 2.8" x 6"
Zero adjustment
1.1 lbs
Input protected
Low battery indicator
Includes case, leads, battery, spare fuse and instructions

I'll second that. I have this one and got it cheaper than $40. Works very well and is more accurate than most DMMs with cap measuring abilities. I do want to eventually get a serious cap meter that does ESR too.

[Cliff Schecht]

Darin check out the Sencore stuff. A used Sencore meter should cost maybe $100-200 and is accurate enough for what we do. I usually measure a known good cap and compare it to the DUT. Make sure to get a meter that checks capacitance, ESR and leakage - all important parameters for e-caps (I know we are discussing pF stuff but ESR is usually irrelevant here..). The nice thing with the Sencore tester I have (aside from it doing L's as well as C's) is that it tests your parts for leakage at full operating voltage which is important to do for accurate readings. On top of this, because the caps are tested at their working voltage through a large resistance to measure leakage, the meter will reform caps nicely. You can actually watch the leakage decrease in real time as the cap reforms!

[dartanion]

Hey Cliff,

Thanks for the info brother! Can you recommend any specific Sencore models?

[Cliff Schecht]

The model I have is a Sencore LC-75. There's one on eBay for cheap but this model has some quirks that make it slow for doing more than a handful of caps in a sitting. To actually initiate a test, you have to push and hold down the button until the device settles (takes some time, maybe a few minutes, especially when the caps need reforming). This I think is alleviated in the newer automated models (LC-102, LC-103) but I have no hands-on experience with these units. I'm sure the intarwebs can tell you what's worthy of testing the caps in your awesome amps .