Dead CM 7000

Mine also quit working properly. It would cycle the power LED between orange and green at a slow rate. This has been reported by several people, including myself, on the Coupon Eligible Converter Box (CECB) CM-7000 thread here at AVS Forum.

This is caused by failing capacitors on the power supply. I replaced mine a few months ago and have had no problems since. If you don't feel you can replace them yourself, send me a PM and maybe I can repair it for you.

mine lasted one month past the warranty.
what caps need to be replaced?

None of the caps on the power supply board are of good quality. Replacing a few will make it operational. It may fail at a later date due to the ones not replaced, but then again may not.

From testing the caps in my unit, these are the one I would replace at a minimum:

C12 - 1000ufd 10v
C10 - 470ufd 16v
C8 - 100ufd 25v
C14 - 4.7ufd 50v
C4 - 1ufd 50v

There are 4 others in the supply that were not grossly bad.

Thanks, I will try replacing those caps.

My board gas 9 normal caps, but c2 is NOT a normal cap
c14 4.7 uf 50v
c13 470uf 16v
c12 100uf 10v
c11 70uf 16v
c10 470uf 16v

c8 100uf 25v
c7 220 25v
c4 1uf 50v
C ??? 22uf 400v I cant read the board to see what cap # it is

C2 on mine is a square yellow box that says 275 vac 40/100//21 0.1 uf
heat marks around u1
heat marks around d7

Thanks for the posts about the bad electrolytic capacitors.

My CM7000 has been in use for about 2 years. It went bad in March, 2011 while we were gone. I thought it might have been a lightning strike but I am using a 2000watt American Power Conversion UPS so it would have been through the antenna. I did not think it was the antenna since it is inside the attic. The antenna does have a small amplifier on it.

The LED was red meaning it could not complete the self diagnostic test.

When I opened the unit, I checked the 3 power supply voltages at the white plug on the logic board. They measured:
+12V supply 12.47VDC with ripple starting at .785VAC down to .005VAC after meter stabilized
+5V supply 5.24VDC with ripple starting at .4VAC down to .005VAC after meter stabilized
+ 3.3V supply 3.275VDC with ripple starting at 1.25VAC down to .005VAC after meter stabilized

I concluded that my power supply was OK so I moved on to the logic board.

ET1, the 1000μF 10V cap had a “domed” or rounded top so I immediately suspected it had gassed and was bad. When I removed it, it checked 0μF, completely open. I replaced it with a nichicon 1000μF 10V cap. The nichicon is slightly larger but there is no problem with having enough space.

I also replaced the two 33μF caps because they were the same color (black and gold) and same manufacturer. I did not need to replace them since they measured 31μF. Since I had gone to the trouble of removing them, I put in XICON 33μF 50V caps.

A note about removal and re-soldering, the negative terminal of the electrolytics is connected to a ground plane copper foil that sucks up the heat. I had a very difficult time getting it hot enough, without damaging the board, to be able to remove it. The positive terminals were not that bad. I set the iron to 450oC, the hottest mine goes and still had trouble. I fired up another butane iron and used it with the electric iron on the negative terminal. It still gave trouble. The soldapult or solder sipper would not suck the excess solder from the hole when I got the caps out. I used very fine drill bits to remove the excess solder. I used both irons at the same time on the negative terminal to re-solder it.

When I put the boards back in and powered it up, the red LED was on for about 30 seconds and then it turned green. I connected it to the antenna and TV and it worked well with the S video output. I tried the channel 3 and 4 output also just as a test and the picture was extremely noisy. I only use S video anyway so I did not try to determine the problem with channel 3 and 4 output.

What was amazing is that when I did a channel scan to add new channels, it found 7 more. We also discovered that many previously discovered channels from when we set it up new had not been working recently but they are now. The picture quality was much improved and exceptionally good compared to what it had been.

I think the ET1 1000μF 10V cap on the logic board had been going bad slowly over time and had impacted the signal.

I believe other electrolytic caps will go bad over time. The case is poorly designed with ventilation slots only under and over the logic board and not the power supply board.

I changed the auto off feature to 4 hours now. I never powered it off before.

The IR detector is not positioned well in the cabinet to work with the remote. I bent it on its leads so it would have a slightly better angle to see the beam.


Original Electrolytic Capacitors
Component Manufacturer Cap. Volt. Temp. Code Group Ca se & Letter Height
mm Dia.
mm
Power Supply
C1 Chang 22μF 400V 105 oC Black & Gray 21.25 12.1
C14 Chang 4.7μF 50V 105 oC Black & Gray 11.8 5.2
C4 Chang 1μF 50V 105 oC Black & Gray 11.8 5.2
C7 Chang 220μF 25V 105 oC Black & Gray 12.8 8.2
C8 Chang 100μF 25V 105 oC Black & Gray 11.6 6.15
C12 Chang 1000μF 10v 105 oC Black & Gray 12.5 8.1
C10 Chang 470μF 16V 105 oC Black & Gray 12.5 8.1
C13 Chang 470μF 16V 105 oC Black & Gray 12.5 8.1
C11 Chang 470μF 16V 105 oC Black & Gray 12.5 8.1


Logic Board
ET1 LH.NOVA 1000μF 10v 105 oC LE(M) H09 Black & Gold 15.25 10.25
ET2 LH.NOVA 470μF 10v 85 oC WP(M) H07 Black & Gray 12.5 8.3
EW1 LH.NOVA 470μF 10v 85 oC WP(M) H07 Black & Gray 12.5 8.3
E6 LH.NOVA 33μF 35v 105 oC LE(M) H09 Black & Gold 11.6 5.15
E5 LH.NOVA 33μF 35v 105 oC LE(M) H09 Black & Gold 11.6 5.15



New replacements
Component Manufacturer Cap. Volt. Temp. Code Group Ca se & Letter Height
mm Dia.
mm
Old bad
ET1 nichicon 1000μF 10v 105 oC PL(M) H9744 Black & Gold 20.45 10.2
Old Good
E6 XICON 33μF ±20% 50v -40-+105 oC Green & Black 11.2 6.5
E5 XICON 33μF ±20% 50v -40-+105 oC Green & Black 11.2 6.5

Attachment 206487

Attachment 206488

Attachment 206489

Darkside,

Bottom line is just replace the 1000uF cap on the logic board.

Many failures across a platform of components is very similar so yours could very easily be the same as mine.

It could also be in the power supply as the others have indicated.

Do you have a way to measure the power at the white plug as I described?

I've seen quite a few computer motherboards and lots of computer power supplies chucked because of electrolytic caps gone bad.
Better brands (ASUS, GIGABYTE, etc.. ) now use solid capacitors which contain a solid organic polymer in place of electrolytic capacitors that use a liquid electrolyte on their high end motherboards. The solid caps don't "gas out", leak, or expand like poorly made inexpensive electrolytic capacitors used in consumer grade consumer electronics.


Electrolytic capacitors....




Solid capacitors.....

I just want to let you know that I had a great experience with sending my defective unit to Whitebar. The turnaround was 1 week, including shipping

You should consider this option instead of buying a new one.

Thanks Whitebar

My Channel Master CM-7000 DTV Converter has also now succumbed to the "red light of death" after 2 years of use. This discussion thread has been very informative and I am ready to do "cap surgery". Are the caps sold by Radio Shack worth installing or should I be looking elsewhere ? Also, for doing this type of work, is a soldering gun much better suited than a soldering iron ? What should be the minimum wattage of the soldering device ? My experience is mainly with 25 watt, 40 watt, & 60 watt irons.

The parts from Radio shack will cost you more than ordering from Digikey or Mouser. Also I do not know what brand and specification of the part, they could be cheap parts.
Refer to this post for a list of replacement part numbers for the power supply caps.

For replacing caps on the power supply a 25 watt iron is good. The logic board caps are difficult, a 140 or 250 watt gun used with care works better.

Whitebar - Thank you for your so very prompt and helpful response, I really appreciate your effort and recommendations. I will check out Digikey and Mouser for the caps and also see what they may have for soldering guns.

If you only need capacitors, Cap King is a great source: http://thecapking.com

My Channel Master box finally red lighted this morning. It has been acting up all week but unplugging it worked after a long reset time.
I bought it back in April '08 I believe. The box lasted a long time for a modern electronic device. Especially the 5 months my niece lived with us, on 24 hours a day.

So repair or replace? I like the idea of repairing it, replacing low cost caps with better quality parts.

Amazing, my second CM-7000 died yesterday, about a month after my first and about exactly as far apart as I bought them. Do these things have usage timers in them ?

Anyone offering reasonmably priced repairs for the solder impaired ?

Besides the CM-7000 (I have one too), is there a Replay/Wirns Friendly D to A box available that folks have good luck with?

Thanks
Cliff

If it is the caps, cost is $18 plus return shipping. Shipping two a time would save on the shipping (to/from) which is more than the repair. Send me a PM if interested.

I have gotten a RCA DTA800 working. It took awhile to find the IR code, which is near the end of the list.

I second HockeyDad99's recommendation of having the CM-7000 repaired by Whitebar. I sent mine to him on a Friday and had it back the next Thursday. It is great that he is repairing these, rather than adding more electronic waste to the landfill.

Kudos, Whitebar.

Under each capacitor (see pic) there is circle drawn on the circuit board. Half of the circle has lines. The lines match up with the negative stripe on the side of each capacitor except one - the 1000 uF 10v. Did the Channel Master assemblers make a mistake? Or should I just ignore the circuit board printout and install it the way the CM assemblers had put it in (reversed)? Thank you
http://i39.tinypic.com/20tl6yp.jpg

Your ET1 1000uf 10v cap IS installed backwards, thus the reason for bulging top. Replace per the circuit board outline. Verified by looking at other units.

The 33uf 35v (E5, E6) most likely are bad even though they measure 31uf. It is the ESR value that cause the part to fail, not the capacitance value. When replacing these, make sure they are a low ESR part designed for DC to DC switching power supplies.

I replaced all the capacitors with new ones. It did not work at first. Taking out old solder to get new components in was difficult on some. I over cooked one of the holes on the circuit board which caused the problem. Whitebar gave some support to get it working. I recommend sending it to Whitebar if you want to save time and energy.

I just found one of my two CM-7000s to be "red and dead", and came looking to see if it had happened to others.

Thanks Whitebar and vsaasv for the detailed notes. I'll be replacing caps tomorrow, which is a lot easy and cheaper than trying to buy a new one.

(my CM-7000s have been on 24x7 since Jan'09 or so... which pales in comparison to the 10 years my RTVs have been running)

Darn. I don't see any obviously failed caps, and none appear to have even a slight bulge...

ciruit board image
power supply image

One of the coils on the power supply (labeled "100") looks odd, but other than that it looks Ok.

I was going to test the power supply from my other CM-7000, so I unplugged it and -- before opening it up -- plugged it back in in the shop. It is now 'red and dead', too.

It is connected to the antenna feed, since my HDHomeRun is down here, so it shouldn't be because it isn't getting a signal. It looks like I'm SOOL.

Looks are deceiving. The caps are bad even though they are not bulged. Check the power supply voltages with a volt meter at the logic board connector. Pins are marked in the silkscreen for the proper voltages.

There are two caps on the logic board that should also be replaced, E5 and E6. These are in a switching power supply circuit and most likely are also going to go bad to the point that it will red light. These two are difficult to replace due to the internal ground plane they are attached to. It takes a lot of heat to remove and clear the hole.

I agree - yesterday I ordered a nearly complete set of replacement caps from Cap King for both units on both logic and power supply board (for under $4 shipped). On close inspection all of the larger ones have what might be a slight bulge, so I didn't want to take chances and decided to just replace them all.

I did check out the power supply voltages - the first unit that failed on Friday had only 4.17v on the +5v and 13.25v on the +12v, where as the second unit the voltages looked fine. However, neither unit worked with the 'better' power supply board.

Cap King didn't have the 33µF caps needed for E5 and E6, so I don't have replacements for those coming. I was planned on doing these last and only if needed, since I'd have to make a trip to 'YouDoIt' to pick them up. But, based upon what you say, maybe I'll reconsider that and do them first.