Dead CM 7000 - Page 2

There is also a 3.3v supply besides the 5v and 12v. The high +12 and low +5 indicates that power supply has a bad C12.

Make sure the caps you purchase for the 33μF 35v on the logic board are "Low ESR" caps. Replacing them with standard caps will result in the unit not working.

Thanks. The 3.3v was perfect on both. I've already got the C12 replacements coming.

I was assuming that most Nichicon would be low ESR -- is there some part or mfg you'd suggest?

Each manufacturer makes caps with different characteristics and the price varies with it. A general purpose cap will be low cost than a low esr.

I have not purchased any from Cap King, but when I looked, the had brand name low esr caps. I expect these will be fine for the power supply board.

For the 33µF 35v, I used either Nichicon UHE1V330MDD or Panasonic EEU-FM1V330

(been out of town)

After replacing all the caps (except E5 and E6), I've got one power supply putting out good voltages, but neither circuit board is doing anything but giving me anything but 'red'. I don't remember if an antenna connection was necessary, so I've even been connecting that when trying. I've not even attempted to do anything with the second power supply (since one is good).

I had hoped to pick up up the other two caps by now, but haven't been able to (out of town). They are my last hope.

I have had to fix mine twice now (bad soldering) and my 7000 wouldn't go green for 4-5 minutes after being plugged in (no antenna needed) Make sure you give it some time.

No antenna connection is needed. The time it takes to go green depends on which of two software version that I have seen. One boots in about 30 seconds, the other about 15-18 seconds.

Mine took minutes both times I fixed it.

I've let them sit for over a minute, but I'll try longer. Thanks for the replies!

Ah... Thank you! I connected the good power supply to one repaired logic board, and when I came back 5 minutes later, it was green. The other logic board didn't go green, though.

I'll recheck my soldering on the logic board. I thought I was careful to not make a cold joint anywhere.

The not-good power supply is reading 3.10v / 3.33v / 11.13v (for the 3.3/5/12). Not sure what I messed up there.

While it went green, when I hooked it up, it only was able to decode 3 of 18 stations. So, I've got it back on the bench.

I declare defeat. I'm sending my units to Whitebar. I should have done so in the first place and saved myself lots of effort!

Got both my CM-7000s back from Whitebar, and both are back in service. I highly recommend him.

(I spent 3 weeks working on them, while the round trip to him and back was just 7 days!)

Thought I'd share my experience.

The 3.3v supply was low (about 3v)
The 5v supply was 6v and the 12v supply was almost 16v.

As per suggestions, I replaced most of the caps on the power supply board. I then plugged it in and watched the led go green.

I realize that other caps might be marginal, but it appears that the power supply board is genuinely defective.

The solid capacitors sound like they're excellent long-term solution. Does anyone have a complete CM-7000 solid caps parts list from a recommended supplier?

Sad News: Steve Inglett:

I emailed Steve to ask about his telescopic mast experience. However, I didn't receive a reply. With a Google search I unfortunately discovered Steve had recently passed away in an auto accident. He was only 48 yrs old.

I had previously corresponded with Steve about his VHF-hi antenna experience. Steve was a member of AVS and most recently learned how to repair his CM-7000 from this thread. I will miss Steve and his blogg.
Edited by ota.dt.man - 6/12/12 at 10:39am

Are you aware of We'll Miss You Gary Leonard! (aka l8er)recently posted over at PlanetReplay?

No, I was not aware about Gary Leonard. It's sad that both he and Steve passed away so early in life.

I have a dead unit, red light on, no led display and no sound or picture. How much to you charge to repair? I am interested thanks.

I too have two of the CM-7000's that were purchased at the same time. One RED lighted about a week ago. Sent both to WhiteBar for repair. Turnaround was less than a week. Very professional job. I highly recommend him. Send him a PM (Personal Message) for instructions...

Keep in mind that on Ebay, these converters are still selling between $50 and $100 dollars for complete models with remotes. I intend to keep mine as I still do not own a DTV. All my TV's are still CRT's.

Thanks again WhiteBar!

Thanks for this Posting. It has saved 3 units from the landfill plus delayed three televisions from never ever land!
Edited by elginite - 3/7/13 at 4:46pm

I've got one red-lighted unit, one that is OK. The only anomaly among PSU voltages on the bad one is 11.65 on the 12V supply. For the other two, I get 4.95 and 3.33, seems close enough. Before I start desoldering on the logic board, does anybody think the 11.65 is cause for concern?

Thanks! This is a great thread.

The +12v is used only in the audio section and is not critical. 11.65 is a bit low but should not cause a problem.
Typical voltages of the units I have repaired are:
+12.06 to 11.91, avg 11.98
+5.19 to 5.17, avg 5.18
+3.3 to 3.26, avg 3.278
Logic board power supply
+1.2 to 1.184, avg 1.192

When replacing caps, make sure to use good quality low ESR caps. Using standard caps on the logic board E5/E6 WILL cause the the light to stay red.

Thanks, Whitebar. You were certainly right about voltage on the 12-volt supply. The PSU from that (faulty) unit successfully powers on my working unit (i.e. the logic board on it).

And the PSU from the good, working unit does not produce a green light on the faulty unit.

On the faulty unit, I've pulled both 33uF electrolytics, the 1000uF, and one of the 470uF. All of them read with correct capacitance. But I understand that your position is, a bad ESR could still occur on one or more and prevent the unit from functioning.

Correct? (I can't measure ESR, as far as I know.)

Thanks again!

To measure the ESR you need a LCR meter. The two 33uf part are the ones that need to be replaced. They are in the 1.2v switching power supply circuit. The other 470/1000 are bulk capacitors and do not get stressed.

It's fixed! Whitebar, you were totally right about the 33uF caps on the logic board being the problem -- despite reading correct for capacitance. I put in some Panasonic FRs and got the green light right away. I then went in and replaced the suggested PSU caps. There'd previously been a hiss coming off the PSU board; interestingly the hiss stopped when the PSU was able to successfully power the logic board. But it would come back on when the unit was turned off. The hiss stopped once the new caps were in place. Also interestingly, I don't believe the hiss was coming from any of the caps, but instead from transformer.

BTW, for the 1000uF cap, I used a 16-volt Nichicon HE, because why not. Insurance. It fits easily and costs no more, maybe less, than the 10-volt.

For desoldering on the logic board -- I actually was able to achieve this with a conventional iron. As everyone notes, it's the ground pin that's the harder one. I first got every bit of solder off the positive side, with a sucker -- till that side was unattached and loose. I then sucked all the solder I could off the ground side after getting it quite hot. After that, I reheated for as much as 20-30 seconds and wiggled the cap from the top side while keeping the pin hot. Once it was loose, I pulled it off. Board was fine, intact. For the new cap, you can simply get the ground lead very, very hot, and then let the lead draw a good-sized bead of solder down into the board. This technique is only for experienced wigglers. It would be easy to burn something, like your hand.

Thanks, Whitebar, you're a hero.