Porter-Cable 8501 question for electrical engineers / technicians / electricians only

[george]

I have a PC 8501 battery charger that is having some problems and was wondering if someone technically capable (i.e., I don't want anyone to get hurt) has an operating one that they can open up and check two components for me. Mine has a voltage regulator that is blasted apart in the middle (where the component identifier is) and a high(er) power resistor that is burned and scorched beyond recognition. If anyone can identify these two components, I'd appreciate it (and I can repair my charger). The voltage regulator is a three terminal device that looks like a TO-220 package and the resistor looks like it is (was?) about 2-3 Watts but cannot read the color bands. I'd rather know what was really in there rather than taking a best guess.

TIA, George

[HMFIC-1369]

Hmm, you don't know what your doing, but want to fix it?

What was the cause? Battery shorted out?

First off if your looking at reverse engineer a battery charger, it's a 12v charger... Go to Radio Shack, or download a 12v regulator data sheet and rebuild it off of that. The Data sheets will give you all the specs you need to build around it and the Battery's spec too. I doubt Porter Cable will give up the chip. Is the Transformer Ok? Caps Ok? unless you know what smoked it and corrected that first the rest is futile. Either build a new one from scratch or buy a new/used one.

[george]

I cannot READ the markings on the parts (and the batteries in the charger are unmarked so I'd have to guestimate a charge rate). I AM an electrical engineer. Currently I am studying for a state exam and do not have the time to buzz this thing out and reverse engineer it (not my first choice even if I did have time). Thanks for your concern... MOST people shouldn't be doing this.

Yep, and it has been recycled.

I know that...there are numerous +12V regulators (and adjustable ones too) with various current output capabilities. It would be REAL useful to know the markings on the regulator so I can find the OEM specs of it or an equivalent. Unfortunately, the batteries are also unmarked (yes, I know they are 10 x

1.2V NiCad and are old technology NiCads at that). Once again, it'd be nice to know their storage capacity. (BTW, I try to never shop at "Radio Shaft".)

See below. Yep. Yep.

Most of the above, I didn't feel I needed to explain to the group as I wasn't asking for help in diagnosing a problem, only information on a couple of parts. As for buying a replacement, they are not available new...haven't seen one used on eBay...but $2 parts cost sounds a lot better than $60 replacement cost plus it would keep this out of a landfill somewhere (electronic products contain lead and other toxic chemicals).

[HMFIC-1369]

First learn from your mistakes, you have a smoked charger, because of poor design. should have smoked a fuse. Why rebuild a smoker. and if your an EE, the time to design a new one was wasted on the email.......

[george]

How's it MY mistake to get the charger that the drill/driver is sold with? And, how is figuring out the required specs a waste of time? Now, either contribute useful info or move on.

George

[george]

I don't know why I was unable to retrieve your message prior to today...but THANK YOU VERY MUCH. You've answered all my questions on the charger. Much of my charger's components are unreadable!

Thanks again, George

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