I'm trying to fix the reverb circuit in an older Crate amp and I think I narrowed it to a jfet in the reverb return circuit. I want to stop at a local shop to see if they have one but they have one but they have NTE replacement parts.
Is there an online NTE cross-ref chart online that I'm missing?
NTE468?
http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search
there is a simple way of testing if a FET is working or not by using a regular DMM.
put the DMM to read resistance. hold one of the probes on either source or drain while touching the gate with the other probe. measure resistance source to drain. now change the probes and redo the test. you should be able to open and close the FET this way and the field should go from infinity to whatever is the lowest R for that type( typicaly 10-100 ohm), and back again. the FET needs to be out of the circuit.
..could be a usefull test to see if the FET is really the problem or not. ;)
J
Quote from: Rodgre on September 28, 2011, 01:02:43 PM
I'm trying to fix the reverb circuit in an older Crate amp and I think I narrowed it to a jfet in the reverb return circuit. I want to stop at a local shop to see if they have one but they have one but they have NTE replacement parts.
What does this JFET do in the circuit? It may be that almost any correct-polarity JFET would work; or it may be that unless it's specially selected, no other device will work.
I avoid NTE at almost all costs. I'd use their parts if there was simply no other option, but in general, they recycle surplus stuff into custom branded products and charge you a lot of money for the privilege.