DIYbanter - View Single Post - Blew another damn transformer on my Trane XB80

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On Thu, 14 Apr 2011 04:43:29 +0000 (UTC), (Don
Klipstein) wrote:

In m, D Nebenzahl wrote:
On 4/12/2011 9:23 PM Don Klipstein spake thus:

I have yet to look at these diagrams, but is the circuit board
powered by this tranny shown to "board level" as opposed to "component
level"? If so, then the board can have, probably does have, a rectifier
not shown in the diagram.

With all the pontificating you've been doing here, Don, I would've
thought you'd at least had glanced at the wiring diagrams the OP posted,
way up there somewhere. Sheesh.

The controller is shown as a block. It most certainly has at least one
rectifier on it, as it contains electronics that no doubt requires DC
power to operate. Thought you'd have figured it out. (Not just a relay
board.)

With such indication even as described here giving low indication as
to rectification having a 1-component bridge rectifier, 4 discrete diodes,
a fed-with-center-tap 2-diode fullwave scheme, 2 separate diodes or a
single 3-lead dual-diode used for that...

If the controller is only shown as a block, how well does it show the
rectifier scheme, as in whether the rectifier's diodes are discrete
individual diodes or integrated into one rectifier package?

If anyone here sees that noted to such extent that it's not a waste of
my time to take a look there, please pipe up!

The block diagram does not show it, but a picture of a replacement
board I found on the net seems to show 4 discrete diodes on the board
- which is what I have found on most control boards I have actually
had my hands on. Being a 2 wire transformer secondary, the center
tapped full wave scenario is a non-starter, leaving either a 4 wire
full wave bridge rectifier or 4 discrete diodes as the only real
options.