Is this scrap??

modelman · Post by **modelman** » Thu Jul 30, 2015 5:52 am

As I troll through the various bits & pieces of the latest money-pit, I found this :

Already ordered replacement grey sheathing, tape, connectors & cabling to make a new harness, so i'm assuming the rectifier is toast? Can I or how do I test it, I do have a good quality meter, If so, are replacements available, if not, what's the alternative.

Thanks.

jleewebb · Post by **jleewebb** » Thu Jul 30, 2015 7:36 am

from my archives, courtesy e3steve...

Testing a rectifier

First disconnect the red (red/wht on C72/77), brown & yellow from the rectifier, as it's not possible to successfully test components whilst in circuit.
With a multimeter, self-powered test lamp or self-powered piezo buzzer, carry out the following tests:

Ready? phasers on stun...sorry multimeter on diode test (or 'beep')
1: probe AC1 (brn) with neg lead and + with pos lead, result should be a short beep
2: reversing probes should result in silence
3: probe AC2 (yel) with neg lead and + with pos lead, result should be a short beep
4: reversing probes should result in silence
5: probe - (gnd) with neg lead and AC1 with pos lead, result should be a short beep
6: reversing probes should result in silence
7: probe - (gnd) with neg lead and AC2 with pos lead, result should be a short beep
8: reversing probes should result in silence

All a diode really is is an electrical non-return valve; positive flow is from anode to cathode (as with all DC circuits), or in the direction of the 'arrow' - this is known as forward current; conversely, negative can be understood to 'flow' in the opposite direction - this is known as reverse current. So think of your multimeter probes (meter on beep) as pos (r) & neg (bk). A good diode will allow forward current (hence the short beep), but will block DC in reverse. A duff diode will either block in both directions or allow flow in both directions. It only takes one diode in a rectifier to mess up the flow sufficiently to reduce the charge dramatically or negate it completely.

I'm open to Qs.

Steve Edwards

DianneB · Post by **DianneB** » Thu Jul 30, 2015 10:02 am

Garbage - don't waste your time on it. Replace it with a new Selenium rectifier or (better yet) with a Silicon bridge rectifier.

Selenium rectifiers "age" anyway and become worse with age, let alone the mechanical damage.

Steverino · Post by **Steverino** » Thu Jul 30, 2015 10:26 am

Steve
Thank you for this post. I am looking forward to going through my little box of used rectifiers to determine which ones are the keepers.
Thanks Again
Steverino

modelman · Post by **modelman** » Thu Jul 30, 2015 11:02 am

would something like this work??

http://www.ebay.co.uk/itm/6-Way-Motorcy ... 1a0093b6bf

DianneB · Post by **DianneB** » Thu Jul 30, 2015 2:09 pm

That's a nice unit! A little pricey but it should work perfect.

brewsky · Post by **brewsky** » Thu Jul 30, 2015 9:48 pm

I got a 25v 50a bridge rectifier at radio shack for 3 or 4 dollars and it works fine.
There are several threads if you do a search for radio shack and/or rectifier