Kirk Morrison on sat 18 aug 01
In a message dated 08/18/2001 12:38:36 PM Eastern Daylight Time,
becketma@YAHOO.COM writes:
> All of the diodes seem to check OK -- I'm not sure about the germanium diode
> as it checks shorted, zero ohms, in both directions. All of the resistors
> check OK and the same in both boards.
>
Diodes should conduct in one direction and block in the other I would say the
diodes have died. Caps will conduct and charge slowly the larger the cap the
longer the time. The diodes from what you say seem to be dead, and I would
replace them and see what happens. My hobby besides potting is rebuilding
tube radios and transmitters for the ham bands, but I am better with tubes,
but I do a little bit of work with Solid State stuff.
Rabbt AKA Kirk AKA KA4PXK
"Honor and Duty, First, Last and Always" R. E. Lee
robert koerner on sat 18 aug 01
Anybody have one for a Brent control board, o30-REVE?
I got two of these boards; one makes my wheel imitate a rock (no movement), and the other makes my wheel go as fast as it can. The first board, rock, I replaced about a year ago. The second board, let go early this morning. All of the diodes seem to check OK -- I'm not sure about the germanium diode as it checks shorted, zero ohms, in both directions. All of the resistors check OK and the same in both boards.
What is left are the caps, and the single transistor. I can unsolder the caps, and check them, but I doubt the problem is with one of the caps.
However, the transistor on the rock board, and NASCAR board have different resistance’s when I measure pins 1&3, 2&3, and 1&2.
Yup. I checked the potentiometer in the foot pedal.
Anyone else having problems with these boards or know how to fix them?
Bob
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Fredrick Paget on sun 19 aug 01
>Date: Sun, 19 Aug 2001 13:18:03 -0700
>To: becketma@YAHOO.COM
>From: Fredrick Paget
>Subject: Re: Schematic for Brent C
>Cc:
>Bcc:
>
>Hi Bob,
>I went thru hell about a year ago trying ,unsuccessfully, to adapt one of
>these to run a Baldor DC motor on an old junk Alpine wheel at school. The
>Brent control is a very rudimentary sort of control. Later I bought a
>Baldor control and used that. Now that is a real control -a real piece of
>work. It makes the ones we get on our wheels look sick. Controlled
>acceleration and braking. Feedback, adjustable in many ways, smooth
>-really fine.
>In the process I traced the wiring diagram (which I sent you separately
>as an attachment).
>As you can see there are no transistors on it . Instead they use a triac
>and diac to phase control the ac line. The theory , etc. of this is way
>too complicated to cover in this letter. Moreover you can't test these
>with an ohmmeter as you tried to do.
>You can buy these parts from Digikey on the web. http://www.digikey.com
>I would try replacing the triac first. They carry all the current and are
>first to go. You can get ten of them for around $30.
>There is a white silicone /mineral powder grease used in mounting the
>triac to give good heat conduction to the heat sink. You will need a
>small tube of that -heat sink grease or Silicon thermal grease,$4.00.
>Have fun,
>Fred
>
>
>
>
>
>>Anybody have one for a Brent control board, o30-REVE?
>>
>>I got two of these boards; one makes my wheel imitate a rock (no
>>movement), and the other makes my wheel go as fast as it can. The first
>>board, rock, I replaced about a year ago. The second board, let go early
>>this morning. All of the diodes seem to check OK -- I'm not sure about
>>the germanium diode as it checks shorted, zero ohms, in both directions.
>>All of the resistors check OK and the same in both boards.
>>
>> What is left are the caps, and the single transistor. I can unsolder the
>>caps, and check them, but I doubt the problem is with one of the caps.
>>
>>However, the transistor on the rock board, and NASCAR board have
>>different resistance=EDs when I measure pins 1&3, 2&3, and 1&2.
>>
>>Yup. I checked the potentiometer in the foot pedal.
>>
>>Anyone else having problems with these boards or know how to fix them?
>>
>>Bob
>>
>>
>>
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>
>
>
=46rom Fred Paget, Marin County, California, USA
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