upgrading irfz's

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
so, i have quite the collection of o/s (90's)amps that i'm repairing, and noticed the mass of them use irfz44, and irfz24's for the power supply fets. well, i have a whole bunch of irf3205's that i would like to put in as a stability/reliability upgrade, and i had a question on the gate resistors. most of them have 100ohm stock, and a few use 33ohm..... i already have enough 33ohm, and some 100ohms. does anyone know if it would work with just using the 33's, or keeping to the stock 100's?
 
100 ohm resistors aren't safe with 3205s unless additional deadtime is programmed into the drive circuit. I generally recommend 47 ohm resistors. 33s will work.

The Z44s and Z24s are easier to drive than the 3205s. In some instances, the drive circuit has to be modified. Before replacing them, post the amp make and model.
 
Sounds like a neet project. If you already got the IRF3205s then you are set. My only experience worth sharing is that IRFZ44/48/50n06 fets are less than half the cost of IRF3205s. Where are you getting all the IRF3205s in bulk? Best I can find is about $1 each.
 
thanx spooney....... i got the irf3205's from tayda electronics. they are .65 ea. in singles. i think i paid a total of like $13 for 25 iirc......... ok, there is a bit of a list in model numbers, so here goes a few of the firts ones i might trow on the bench......
targa q58mx
pioneer gm-x302
power acoustic 4apc-960
(haven't even opened yet, so maybe)kenwood kdc-x811d
hifonics cyclops 100
..... thanks guys.
 
ok, the wierdest thing just happened, i threw the kenwood up on the bench, adn aside from the wierd output design, all of the caps are missing..... i'll start a different thread when the time comes, but back to the task. tonight, i'll be doing the power acoustic Apache 4apc-960. it has the 44's and 100ohm resistors. the whole amp is pretty simple, and so is the drive board. there also is the 220 ohm resistor between emmiter side on the board, and drive, before the base resistors, just in case that value would make a difference...
 
ok, well, i had momentary success. the power supply side that was originally blown held good and powered up fine and held music, however, i believe d10 was a bit faulty and the fets on that side blew out after a min of play. the amp had a lot of dimming on the needle displays and the voltage i picked up there was lower than the other side. i'm going to leave it until i get back from work (3weeks), but do you think that that diode could be the culprit? i could not find replcements through google, and the 2 suppliers. the numbers i got off of both are
C2573
l>l-l<l
02C (THE ONE IN QUESTION)

C2573
l<l-l>l
02N

any help appreciated...
 
The part number is ESAC25M-02C if you want to try to find the original. The MUR1620CT is a suitable replacement (electrically) but you'll have to use insulators, shoulder washers, etc. to insulate it from the heatsink.

It's rare for rectifiers to fail. Are you sure that it's defective?
 

Attachments

  • ESAC25M-04N.pdf
    140 KB · Views: 54
no i am not, but i would like to find one just in case, and thank you for that. i'll dive into it when i get home and post up some questions then, when i get readings..... however, i do remember taking some and got good rail voltages, or at least i think they were good( don't know what this amp is supposed to run at) with no blown outs. it was just when i played that channel that it soon after just killed the fets. i don't remember if i even got sound, i just remember messing with the rca's and it shut off on me. (thought i let the sla run too low) and then i charged it and powered up the amp and a resistor smoked. the whole side tested bad... boy, i just need to go pick up a better power supply, lol..... but i'm just doing this as a little hobby to entertain myself and not go completely dumb from work.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.