drd431rg dead / no power help!!!

[darak]

I have a drd431rg that won't power up! is there a quick fix for this like the drd420re's???

thanks!:(

[darak]

this receiver has not been modded yet. just suddenly died. i did open the box and couldn't see anything obvious like a burnt trace or blown fuse. i do hear like a humming sound when it's plugged in.

is this box totally dead???

[valenti]

Sounds like the power supply is dead downstrwam of the transformer. What you hear humming is probably the transformer. If you know anything about electronics, follow the secondary leads out of the transformer, and test for voltage along the power supply chain. If you don't know anything about electronics DON'T DO THIS. Find someone who does know something and ghave them check it out for you. It's not really the kind of thing that can be diagnosed specificaly over the web, but I can tell you that I've fixed three of them (one 420, one 430, and one 431) and it was the power supply in all cases. All of the supplies were different, but it was typically a cap or diode that was gone...all available at crazy prices at Rat Shack.

valenti

[darak]

thanks valenti... maybe you can walk me through the process...i will take some readings this afternoon and check out the voltages... PM me if you have time.

[m5runner]

I have a problem with my 430RG too. I was trying to mod it and now the power doesn't come on. I can hook Jkeys back up to it and all that but the light doesnt come on when i do the "write byte" to tell me that i am going the right way. i was looking at the schematics but it doesn't show me where the +5V goes. I am sure it can come back to life but I think it won't because I already messed up the flash. if someone can help me out that would be cool. I am using Jkeys 2.9.....when i go to dcu trap and attempt to write the bytes to it and when it's supposed to return 80, it returns FF. I am guessing it's my wiring. any help would be cool.


M5

[darak]

@ valenti, can you tell me what designations/locations on the caps or diode that you replaced on the 431 rg? maybe i can isolate the problem a lot easier this way.

thanks!

[valenti]

OK, I'm gonna open up the 431 that I still have here and I'll get back to you right away. The 431 had the most extensively blown PS.

valenti

[valenti]

OK darak here we go.

First off, you said you can hear humming??? Is it loud enough that you can hear it no problem or do you need to listen very carefully for it. I can JUST BARELY hear any humming coming from the transformer in mine.

At any rate, here's what I replaced in my 431. Take the top off of yours, and position it with the back facing you and the power cord to your right.

If you look around the outside of the board, you'll see markers used to locate positions and components. For example, there is a large resistor located at GG-14. If a component falls between or across two locations the designation might be for example A fuse at AA-3/4.

Here's what I replaced.

1. The 100uF 220volt cap at AA/BB-9/10. (it was swollen)
2. The Diodes at locations AA/BB-8 one was cooked, but I replaced all four. This is basically a rectifier set up.
3. The 2 caps at EE-14 and EE-15. (Both were swollen) Those are 6.3 volt 3300uF.

4 The 220ohm resistor at location BB-14. It was looking a little cooked.

Now the last thing I did was to add a MUCH larger heat sink to the voltage regulator at location CC15/16. I'm no electronics expert by any stretch of the imagination. BUT for some reason the regulator on THIS 431 gets SO HOT, it feels like the top of a full CLASS A power amplifier at idle...IT's just boiling, and the supplied heat sink just didn't seem to be dissipating the heat very well. The odd thing is, that in another 430 I worked on once, the same regulator got just hot to the touch.

At any rate, good luck with yours. Also, if you can't find an exact match for those components, don't worry too much about it. Just get something that's as close as possible. Go bigger on the diodes, resistors should be no problem and the caps you can get pretty close. For example you could use a 4700uF 35 volt cap for number 3 above as long as it physically ft in the case.

I think the problem is going to be to identify the components that have failed. I would think that if you can hear the transformer humming, the problem is downstream from there.

One other thought though. Is it possible that you dissrupted the ribbon cable from the switch panel to the main board on that thing???

good luck

valenti

[m5runner]

from my experience as an engineer, when transformers go bad they usually take diodes out so look closely at your diodes. all the info other guys gave u can be right also. first thing i would look at are diodes. if you had a tracker your troubleshooting would cut down to about 15 minutes......5 if you really know what you are doing. anyways, we all know that a tracker costs from 10 to 30 times as much as a new IRD on ebay. keep testing


M5

[darak]

well, no luck with my problem... i'm starting to think it's not fixable. i did notice that the 220 ohm resistor has a reading of 1 ohm...could this be the problem?
could someone verify that this is infact 220 ohm?

anymore suggestions anyone???

[valenti]

If your talking about the one at location BB - 14, it is a 220 ohm. If you are testing it with both leads soldered into the circuit board, you may be getting a false reading, as your meter would/could be shunting through some other path (of least resistance.

valenti

[valenti]

This is from another thread, and might help those of you with dead 420's...sorry about posting a cut and paste from anoher thread

This is a cut & pasted from “Subman” at: http://www.dssftp.com/forum/upload/...19883#post19883

After doing a lot more reading (and trouble shooting), found CR14108 was shorted. I replaced the damaged part (BYW100-200) with an NTE587, but I used an NTE588 which had a better spec, this should fix the problem on RCA DRD430RG 100%, I also tried on my RCA DRD430RG it work like a charm. But do not use RadioShack P/N 276-1102 a pack of 2 costs .69 cents to replace CR14108, this will not work on RCA DRD430RG as I’ve tried, it will smoke, I was wrong as my 1st posted, but base on “Subman” info that I’ve tried on my RCA DRD430RG, I was able to correct the problem that I had. I also found that on RCA RDR420RE has the same CR14108, if some if you had this kind of problem, you can always give it a try, Good Luck!

PS: You can buy this NTE588 at: http://www.circuitspecialists.com/prod.itml/icOid/5558 or check with your local electronic store, I bought my on a trip to NY, at a local electronic store for $2.00 a piece.