RT-246 circuit breaker

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M151A2run
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RT-246 circuit breaker

Unread post by M151A2run » October 18th, 2016, 8:24 pm

Can anyone tell me how to get to the circuit breaker in a RT-246 without tearing it apart. I want to check it to make sure it is resetting or not. My unit stopped transmitting but still receives. Thanks for any help!

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rickf
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Re: RT-246 circuit breaker

Unread post by rickf » October 18th, 2016, 9:59 pm

If it has power I would guess the breaker is good, Did you have a good antenna connection?
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Re: RT-246 circuit breaker

Unread post by miljeep » October 19th, 2016, 4:50 pm

Are you asking about that because when you 'key' the mike the fan does not come on, I only ask because Ive been told that might be a fix for that problem.... Scott O&O

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Re: RT-246 circuit breaker

Unread post by rickf » October 19th, 2016, 5:30 pm

And I asked about the antenna because if you keyed up without an antenna you may have burnt out the finals and therefore will have no transmit. Give us a bit more info and we can help you.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

M151A2run
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Re: RT-246 circuit breaker

Unread post by M151A2run » October 20th, 2016, 6:42 pm

The finals could have burnt, but I was wanting to check the circuit breakers first to see if they were triped and not resetting properly. I will definitely need help trouble shooting this thing if not the breakers. Thanks

kmam
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Re: RT-246 circuit breaker

Unread post by kmam » October 21st, 2016, 5:48 am

I figure it will be the same as the 524 and a symptom can be rx OK. But no fan/xmit.

They are a problem to get to and work on. To do it properly you need to remove the front panel and the step-by-step instructions are in the service manual. FOLLOW THEM EXACTLY! Be particularly careful of the multi pin connectors when reassembling as it is easy to bend a pin and then break it - experience speaking.

If you remove front and/or back panels be VERY careful to keep the gears in alignment.

If you are not comfortable working with this gear, get it done. I posted some time back contact details for a guy in the US who does these sets.

If you are careful you may be able to put insulated probes onto the circuit breaker (there are two breakers) and check for continuity.but watch out as there is a high risk of shorting the power and also doing other damage.

Goid luck.

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M151A2run
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Re: RT-246 circuit breaker

Unread post by M151A2run » October 21st, 2016, 1:42 pm

I was afraid I was going to have to tear it apart. I do not want to. The rt-524 was easy to check. But the RT-246 you can't even see them. Thanks

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Re: RT-246 circuit breaker

Unread post by snock » April 20th, 2017, 9:43 am

I wouldn't worry about the breaker. If the fan doesn't come on when keyed then it's likely that your A9400 module is bad. It's the finned heatsink unit on the side of the radio and is easy to replace. Together with the A9000 module these two generate the 115VAC for the fan and the high voltages for the tubes. You can check the transistors with an ohm meter to see if they're shorted. I've just replaced these in the past with modern equivalents in a TO-220 case but that requires drilling and tapping 4-40 holes for them to mount up to the existing heatsink.
1964 Kaiser Jeep M151
1967 Cemsco M416
1989 AM General M998
1986 Chevrolet M1009

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