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Hi Guys,

this is my last Vintage ESC lying around, I have 2 actually, one is working and another one is fried due to reverse polarity. I think the Break is busted.

I have pulled out the fried FET's and hoping it can be replaced with a good working replacement FETS.
if anyone can lead me to the parts equivalence of these FETS, that would be great.

Since I have a lot of time on my hand, its worth wasting time on. So please bare with me.. Thanks.

so here it is as it sits



heres the busted fets.







any help will do.

My Twins, one working ( Left) one busted ( Right).




thnks,

Well here is the datasheet for the RFP50N05 if it helps any:

http://www.datasheetcatalog.com/datasheets_pdf/R/F/P/5/RFP50N05.shtml

I've had no luck so far with finding a modern equivalent. Maybe check ebay for NOS. I've had a lot of good luck finding obsolete electrical components that way.

Edit:
Here we go, straight from Hong Kong:
http://www.ebay.com/itm/50A-50V-0-022-Ohm-Logic-Level-N-Channel-Power-MOSFETs-RFP50N05-RFP50N05L-/221317023090?pt=LH_DefaultDomain_0&hash=item338785c572

the reason you can't find modern equivalent parts is that they are rated for much higher current than possible back then. So you might find an equivalent that is now a 60volt, 70A FET in that package, and those specs are part of the new part number. So find that family of parts, look for one similar, and you can't really do bad things by picking a part with slightly higher specs. DEFINITELY don't pick one with LOWER specs unless you really know what you are doing.

the PBYR1635 parts look like diodes, so you can do a diode check on them to see if they are really broken. If so, you can find equivalent parts, but they might have a different package.

cross reference shows MBR1635 is replacement:
http://www.onlinecomponents.com/general-semi.-mbr163545.html?p=28447121

on a quick check, this part should work for the FET replacement, in fact, should work for most ESC's of this era:
http://www.onlinecomponents.com/fairchild-rfp70n06.html?p=11369061

available many places

Thanks guys might need to have a look later.


Sent from my Nokia Star Tac using Tapatalk

I was checking the replacement for rfp50n05 and found out that I can use IRFZ46N, not sure if the datasheet is compatible but its the same its just the resistance is slightly lower ( 16.5m Ohms) instead of the 22m Ohms. will that be ok? or should I just get rfp50n06 instead?

Use the one I showed you. Its really the same part with better yield.

ok, will do. thanks

just to update this post. Now, both esc are busted . reason : reverse polarity.
just bought the replacement parts. hope thats only the parts needed and will work. wish me luck

slow_jun wrote: ↑Mon Jan 15, 2018 2:20 am reason : reverse polarity.

with T-plugs?!? That's amazing

Keep us posted how the fix goes

There are several things which have to be considered.
The PBYR 1635 is a power schottky diode indeed and could be still working. If the case is not broken or split you have to do a diode check with a digital meter, which need to have a test circuitry. Applying the test leads you should get a 'I' and reversing the leads you should get a reading of around 200. In this case the diode is OK. If you get a '000' the diode is burnt.

For the FET, you can´t just replace it with any other type. One reason is, if this FET has lower internal resistance it will carry more load and in the end will be overloaded and burn again. Also some FET do switch different than others, this depends on internal capacilty. So all FET's should be of exactly same type and batch otherwise there could be problems.
Another problem is, there could be some FET's which look OK from the outside but are shorted or are not working. They could affect the whole ESC working erratic and burning again. It´s not easy to check if a FET really does work OK, a usual meter check can´t do it.

A main problem today is current FET's do work different. If you search at Ebay you will find most FET's carrying a 'L' at the name or 'logic level' mentioned. This means they are controlled by a low voltage of 5 volts or less. FET's of old ESC's were controlled by a much larger voltage. We talk of 8 - 11 volts for some ESC and 20 - 30 volts for some very special ESC. Using logic-level FET's at old ESC will kill them in a second.

When working with FET's you have to care about static discharge so touching them with your fingers could kill them again.

Lonestar wrote: ↑Mon Jan 15, 2018 4:09 am

slow_jun wrote: ↑Mon Jan 15, 2018 2:20 am reason : reverse polarity.

with T-plugs?!? That's amazing

Keep us posted how the fix goes

No bro, used 4mm Bullet con. was using shorty batt when i hooked up wrongly ;-(

sorry to read - thought it was the left one above that was working, and it was shoiwing T-plugs...

Ordered the parts,waiting to arrive and fix. Hope it works .