Need Help R2024D won't turn on

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j&b
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Joined: Wed Mar 30, 2011 5:12 pm

Need Help R2024D won't turn on

Post by j&b »

Hi guys this is my second attempt so sorry if it is a repeat I seem to have lost my original post with the "Sign in Process"

Anyway

I have a R2024D that had a burnt trace on the main board going from the voltage selection switch in the back to the A3 Board. I diassembeld the bracket from the A3 board and the bracket was bowed so the 2 outer larger caps C1 and C3 legs had "Arced" to the case. I cut the legs shorter jumpered past the burnout and it is no good. I did check the transistor and Diode on the board while they were off and the caps were out of range on my meter but they do appear to charge/discharge with an ohm meter. The only voltage I have found on any board test point is on the A3 TP 1 has 15.4 volts DC in on and off switch positions and TP 2 has 32.8 volts DC when off zero when try to turn unit on.

It does have the oven light on and makes a "Chirp" sound from the speaker when I first try to switch on. The fuses on the back and on A3 board are good.

Without a schematic it is poke an hope. I am tired of spinning my wheels so...

1.) Ebay has a R2001D service manual scan will this cover my 2024D?

2.) does anybody have a "Good" A3 Board? schematic info, and or a stand off for troubleshooting available to purchase?

3.) what is the NE1 neon bulb on the main board there for? is it suppose to light? I have never seen it on...

Thanks for taking the time to read this and if by chance you can help me or point me in the right direction it would be appreciated.

Brian
DJP126
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Re: Need Help R2024D won't turn on

Post by DJP126 »

Hi Brian & welcome to the board. To answer your questions.....

1) IF the pdf on Ebay is a SERVICE manual for the R2001D, NOT the USERS manual, it does cover your R2024. The basic unit is the R2001D, any change in the model number from there signifies the options installed.

2) Good luck finding an extension board for troubleshooting. Motorola did offer an extension board kit, but they were VERY expensive.

3)The neon bulb was used as an overvoltage protection in case somebody had the voltage select in the 110VAC position and plugged the unit into 220VAC. If this happened, the unit would continuously blow the fuse.

The A5 board is the LVPS Output. The test points should read +5, =5, +12, -12, +110, -110 & +35. All voltages are DC to chassis ground. One of the test points (TP1 or TP8) is also ground. Sorry, but I don't remember which test point is for which voltage. If you do get a copy of the service manual, there is a good troubleshooting procedure for units that won't power up.
Dave
j&b
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Re: Need Help R2024D won't turn on

Post by j&b »

Thank you. Kind Sir for your quick response and info. I will order the scan today. It is both a service and users manual.

3 steps forward today! Just hope the hysteresis loop I am riding doesn't take it ALL back.
j&b
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Re: Need Help R2024D won't turn on

Post by j&b »

Dave you ROCK...as an Idle American should!!

I was as sketchy about purchasing documention for a R2001D, your info helped me decide to go for it. I made it to step 3 in the front of the troubleshooting for no power up and nailed it A5 no voltage. (Of course you were there days ago)

The R2001D manual on Ebay bay by "Southerncross" is exactly what I needed the scans of the service maunal are definately usable ( I printed and taped together the larger schematics and board scans for the low voltage power supply and they all lined up well, if not exact. missing about 1/2 of a letter width in center but put in context an EXCELLENT reproduction. Owners manual has some rounding in what was center of book but also very usable)

Step 3 was to verify no shorts from A5 Board TPs to Ground. There isn't any that should...(Sorry Dave no GND or TP8 on the D series) TP1 is +110vdc, TP2 +33v, TP3 +12v, TP4 -5v, TP5 +5v, TP6 -12v, TP7 is -110vdc. (Sorry Dave no GND TP on the D series) They all are diode through Xformer to ground with a parallel RC network to ground resistor 270ohm to ground on the 5v lines and 2k or larger on the others.

Mine was TP2 the +33v line was shorted on the board through C9, it is the small style, (NOT THE ELECTROLYTIC), or the diodes, (MUCH to my surprised) I had lifted and tested them 1st. Just a helpful tip... The over current was shutting me down.

Again it lives!!! I took the $$$ I woulda spent to replace it and bought me a Stereo Microscope (I am gonna label it "from Dave at Batboard") for my solderstation, Now maybe I can see those da@#$%^ little parts they put in radios these days... Thanks again to Dave for the input, he helped save another one.
DJP126
Posts: 873
Joined: Wed Jun 18, 2003 6:41 am
What radios do you own?: What's a radio?

Re: Need Help R2024D won't turn on

Post by DJP126 »

j&b wrote:Dave you ROCK...as an Idle American should!!

(Sorry Dave no GND TP on the D series)
Just goes to show that I'm getting old. LOL (At my age that means "Living on Lipitor"). :D
Dave
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