Search results

These are just two examples of why I inspect all my circuit boards under a 100X digital microscope.

Gary, if you did not change the Bias Transistors from the original 2N3403 devices, that may be the issue. We use newer 2N5088 devices because they track with the heat a little better, and they are current production. The 350mV Bias setting was a compromise. 300mV gave us a cooler running...

Millguy, it will take you awhile to make as many mistakes as we all have with these upgrades.

Clearly, ordering these older spec parts is a moving target. When I looked - C15, C16 were not available at Mouser, now they are? Sheesh! TAW is awkward, you have to fill out a Parts Inquiry, then they contact you with the amount in stock and a price. It was the only place I found that had...

Mark, you are correct. I could not find a C26 in my PL2000 Series I and C25 is deleted in Series 2. George and I were corresponding during our PL2000 upgrades; he was doing a Series II and I was doing a Series I. He may not remember but he showed me a picture of his Mica Capacitors in the Mouser...

Mark, this "Kit" has about $25.00 worth of capacitors in it (if purchased in high quantities). Also, he is offering ceramic capacitors which are inexpensive and not optimal for audio. I would pass. Between George S. and myself, we can come up with a P/N list of the capacitors you need: C1...

I second that motion... I finally found a decent Transistor Tester, a Sencore TF-151A. I had to change out the electrolytic capacitors. There are better transistor testers out there (I think the TF-166 has more bells and whistles), but this one does test Gain in a High and Low range (Power and...

The snubber is an attempt to reduce contact arcing in the event of a amplifier failure when DC voltage has caused the relay to open the contacts. The capacitor charges, reducing the arc, and resistor bleeds off the capacitor. I may try it and see if the Snubber has any effect on the load of...

Experimenting is always in order because there are compromises as others have stated. This is a starting point based on the following formulas: 1.2 Ohm 2W Arc Quench Resistance R(q) = V(t-arc min) / I(L) and 25uF Arc Quench Capacitance C(q) = V(s) / {E(BDN) x V(co) x R(c)} Where: V(t-arc min) =...

There were two nominees - Jeffries and Jordan. Two Republican Representatives voted for McCarthy. We are doomed.

If arcing across the relay contacts is a concern, could we just use the Zobel RC Network (R1/C8 and R2/C9) positions and insert the components for a Snubber Circuit for "break" arc suppression across both sets of relay contacts? Using a maximum (VO) voltage source of 80VDC for a PL400 and a (RL)...

MusicSteve? WOPL Sniffer?

Thanks for the assist. You took the troubleshooting words right out of my mouth. Spot on. The Bring Up Instructions are very generic and meant to apply to a wide variety of upgrade scenarios. The 10K resistors give a path for current flow from the outputs to the Chassis; current will take the...

Paul, I would replace the Negative Rail F2 fuse, it clearly blew when the rogue washer shorted something. Your voltages will not be correct with F2 missing in action. Then if the Bias cannot be adjusted, you will know the Bias transistor will have to be replaced. Here is a little secret - the...

I need to find solder paste masks for the DIP8 and the DIP14 style OPAMPs.

Paul, You might eliminate half of the possible components if your Left Speaker DC voltage is positive or negative. You did not specify. Did any of the Backplane Boards fuses open? Where did you find the washer? If it was between the Left Channel Backplane Board and the Chassis... If the Speaker...

According to Hall of Fame defensive end Deacon Jones, Butkus "was a well-conditioned animal, and every time he hit you, he tried to put you in the cemetery, not the hospital." In 2009, the NFL Network named Butkus the most feared tackler of all time.

It was nice knowin' ya.

Jim, Did you use hot air for soldering the SMDs? If so, which hot air gun do you have. I am looking at a few.

Lee, what is the going price for a unburnt, working, useable PL control board? I was thinking: PL14 (P/N 55600).........$10.00 (may have the 6.3V caps reversed) PL14A (P/N 7040)........$12.00 PL14B (No P/N)............$15.00 (comes in gray large size and green small size) PL20 (P/N...