Channel Master CM-7000 Digital to Analog Converter - Page 48

They still have some.

RE:
Channel Master D2A box

Put in a header for the jtag port and used jtag_p to dump the 2Meg flash and 8 Meg of RAM. The main part of the bin is gzip compressed, so that is part of what takes so long for this box to come up. Code is st20c1 and IDA Pro can disassemble that--not well, but not all that bad.

Would post the dumps but they are too big for the limit on zip.

Rough memory map of flash:
0x40000000 base addr is the boot area
to offset 0x20000 where you find the gzip compressed main bin
offset 150000 a data area--maybe box data or something tied to scan
offset 180000 channel data--looks like this is a cumualtive set of all the scans made as there are multiple duplicate channel names.

RAM base addr is 0xc0000000 and the decompressed main bin starts at this addr and is roughly 2.5Mbyte in size.

It should be possible to use the ucTap program with the ST Toolset to write the flash.
2.1.2 ST Toolset has info on a STi7710 chip and that chip has the same product ID as what I found with jtag_p check of IDCODE for the STi7707 chip, so sould be able to find info or datasheet for the 7710 and use that info for the 7707--might just be a different package.

Boot code has lots of ascii strings that indicate that some product development board had serial port support and that that was used to burn flash, but I don't see any trace of serial port support on the D2A board.
Maind code has a menu for development too that I'm guessing was disabled for the released form but might be able to get that called up with machine language mods.

Just wanted to report additional CM7000 experiences. I bought two CM7000s at the same time about 3 years ago. Both recently failed within 2 weeks of one another. I replaced all the electrolytics and both have come back to life. Neither of these were left on all the time. Clearly the components used are not of the best quality. Usually electrolytics can be expected to last at least 10 years. So if you own an older CM7000 you better start buying capacitors. You are going to need them!

I use to repair old vacuum tube radios, the most common problem was failed electrolytic capacitors. The average age requiring replacement was ~30 years for the tin can type to ~40 for the waxed paper capacitors(not electrolytic). <5 years is so pathetic it makes me sick, more things for the landfill in our disposable society
FWIW all 3 of mine are still working, although they are lucky to get turned on more than a couple times/year. I don't know if it's better to have them plugged in or unplug them but mine are buried in a enclosed rack and unless they start smoking they will remain plugged in
I now record everything to my Tivo HD so I no longer really use my CMs to feed my analog DVDRs, only rarely for scheduling conflicts.

The two year life of some of these capacitors seems to be a combination of:
1: A bad vender
2:Insufficient voltage headroom spec's. (ie 6Vdc rating in a 5Vdc circuit)

Totally agree with you on both points and they both probably come into play on something as cheep as a CECB
Not that the CM was a cheap box, I paid upwards of $70(without a coupon) for mine(ordered before the coupons were available) but unfortunately even $70 at the retail level can't buy many quality parts...
Use name brand replacements with a voltage rating +50% of the original and they'll probably last a lifetime(or until the next cheap parts start to fail). Heck my CH UP CH DOWN buttons started failing(skipping) after only a month or so of use, can't really use them any more.

Mine and others I've read about did that out of the box so it appears to be a design flaw > lack of switch debouncing caps. Something like 1000 pF required on each of the UP and DOWN lines to ground, should be easily kluged (there could even be solder pads in place but they didn't place the parts). There were some posts about it here but I don't know if anyone actually performed the kluge.

I would like to get a good universal remote for my CM-7000. I know that most U-remotes will work with the cm-7000, but I'm looking for one that will allow me to access most of the converter box's features (like info, EPG and menu).

Any recommendations?

I think an alternate remote code has been mentioned, possibly panasonic.

That would expand your options.

The information is on here somewhere.

I use an inexpensive 3-function Philips u-remote. Gives me all those functions but no Wide, FAV, or the subtitle and text stuff (Wide is the only one I miss, CM's FAV is useless IMO). I suspect the higher number function Philips as well as many of the other brand of newer u-remotes would be similar. CVS had the 3-function Philips u-remote free after extrabucks reward again this holiday season so watch to see if it goes on sale again. My store just restocked them.

The CM manual says to use a Pioneer cable box code for older remotes.

What model is your Philips remote?

SRP1003/27. Bought it a year ago but I think CVS was still selling the same model this year.

I just got back from my CVS and they have SRP1103/27 models. I think the buttons and layout were the same but slightly different shaped body.

Of course CVS wants too much if you can't get the rebate deal, 12 or 13 bucks. I checked Amazon and $8 + free shipping:

http://www.amazon.com/Philips-SRP110.../dp/B004PYKM1Y

Scroll down and you'll see some other models too like with bigger buttons (even cheaper for some reason), glow buttons, and/or can control a higher number of devices.

Of course Walmart or similar will have better prices than CVS but I don't know what models they carry.

Thanks for the suggestion.

I spent a few days reviewing the SRP1103/27 with other remotes, and I figured out that a good way to know a u-remote is compatible with DTV boxes, is to check that it has MENU, GUIDE, INFO and (-) buttons.

So I went down to K-mart today to compare u-remotes and I liked the philips, the other brands had really bad confusing button layouts. Since everything at the K-mart is always over priced, I went and got the SRP4004/27 off of ebay for $6.49, it's the same as the SRP1103/27 but it's physically bigger and has buttons that can glow.

I'm now waiting for the remote to arrive in the mail...

You're welcome!

Probably true for newer remotes but I've got an older one that I could only get to do power and channel. Don't think it has a (-) button though (pre-DTV). Some like the 1103 list it on the packaging or a sure-fire way is to ask the store if you can open the package and verify your device is listed in the manual or download the manual off the 'net.

Nice and great price! Actually you get to control an extra device since it's a 4-function remote. I like the big and glowy buttons too. That old one I mentioned lights up but it lights up red so hard for me to read; plus the lighting kind are battery eaters.

Let us know how it works out.

Just wanted to toot my horn for this box and it's ability to handle multipath! besides I can't believe it but no one has posted in this thread for almost 1/2 a year....guess most people interested in such a box have already purchased one.
Since the leaves have come out and especially the last few days when it's been extremely windy I've been having multipath(breaking up) problems with several of my lower digital channels. It's not weak signal(I live <15 miles from antenna farm and signals are generally all in the 90s with my attic antenna). Anyway, with both my Sony HDTV(couple years old) and Tivo HD(also couple years old) I've been having picture break ups on the lower channels ~every 5 seconds when the conditions are windy(normally I have absolutely no reception problems) . With the same antenna connection I hooked up my CM-7000 and PERFECT, no breakups. Switch back to Sony or Tivo and breakups return. If this isn't proof positive I don't know what is. I also have a Zenith DTT-901 that may hold a very slight edge on long distance reception, when I hooked it up it had the occasional breakup(still much better than my TV or Tivo).
So there you have it, if you need a SD CECB and need one with the best possible multipath reduction I'd strongly(as I also have in the past) suggest the CM-7000. If your more interested in long distance(DX) a Zenith/Insignia might also work for you although the CM is also very good at week signal reception(better than both my TV and Tivo from tests in the past).
I have 4 CMs and they are all working just fine although I've read(in this thread) a few people have had issues with premature capacitor failures, also something to think about if purchasing a older box. Mine have been plugged in(but mostly off) since purchase(several years now) so I don't know if that is better on the capacitors than storing them unplugged, I don't know.

I've had some powered up since I got them.
No failure.

They do seem to be more capable than anything else, though I have found times the TRT will lock in, when the CM won't.

I have an older highend hidef LG, which has trouble locking in, but seems very tenacious once locked on a signal.
I suspect it will outperform the CM, if it can ever tune in.
It is slow in bad conditions.

I agree; I have the same experience with less breakup on the CM than my Tivo. Glad I bought two of the CMs though, because one just up and died a few months ago. I've been reading about potentially bad capacitors, but they look fine visually, and I don't have the means to test them with a tester. Curious how many other CMs have died?

Dead here. Changed one of the caps and fixed it the first time...Guess I should have done them all. As now no joy after changing them all.

Any chance it's a bad solder connection on one of the caps? Also, did you change those on the power board too? After having the same type of thing happen on three different products (CM, Slingbox, 2Wire modem/router), I'm beginning to think that's the new way of building in planned obsolescence.

Was your box stored for quite some time or if plugged in was it generally OFF or did you disable auto off so the light was green all the time?
Just trying to figure out why some(including my 4) work fine for years(plugged in but mostly in standby) but others experience such failures...


IMO It's a disgrace, properly spec'd and of a decent quality, electrolytic capacitors should last for 30 years or more, at least devices made in the 60s for the most part aren't experiencing such issues
With things having only a 90-360 day warranty their isn't much a consumer can do, other than just not buy much. The sad part is most of these boxes were hooked to older TVs, which are still probably working after the CECB fails
Even purchasing a name brand like Channel Master apparently isn't a guarantee they'll use high quality components.

I have repaired about 20 units. Some people have sent two at the same time.


You unit most likely is still repairable. When you say you replaced them all, which caps are you referring to?
All 9 on the power supply?
Did you replace any on the logic board?
The type (not brand) of cap used in replacing can cause the unit not to work. The caps need to be a low ESR type.


I think all of the ones I have repaired, all have had the auto standby disabled since they are connected to ReplayTV DVRs. I would expect units mostly in standby to not fail nearly as soon. In standby the unit draws about half the power. This results in lower ripple current in the caps lowering the temperature of them. Lower temps = longer life.

The first time I only changed the one that was swelled-up like a football....closest to the large diode. It ran for a good year before it went down again. The unit was always on, from the time I first bought it, as it fed a ReplayTV DVR. I replaced them all on the power supply board and 2-3 on the processor board.

I had a bit of an issue with the few on the processor board I replaced ...seemed a bit difficult to get them out. Like the heat wasn't getting all the way through. I wonder if these are multi-layered boards??? I feel the caps on the power board were done right, perhaps I got a bad one or two. Although I had all the voltages present at the connector. But of as I recall I had them all the first time with the visibly swollen cap. As I recall, perhaps one was fluctuating a few millivolts the first time.

Yes, all on the power board, and 2 or 3 on the logic board (that I could find)
I can't say if they were "low ESR" or not...only went by the values. Perhaps that's the issue.

The logic board is a multi-layer board with internal ground and power planes. The ground plane acts a heat sink and that is why they are hard to replace.
It is probably E5 and E6 on the logic board that is the problem. They are used in a 1.2v dc/dc power supply. They are 33uf 35v and must be a lower ESR cap or it will not work.

Wishful thinking.
Cheap electrolytic capacitors are only rated for 1000 hours or maybe no rating at all. That's a MTBF number (an average expectation) rather than a guarantee. Decent caps would be rated 2000 hours, and "long life" would be 10,000 hours, but you're not going to find those in cheap consumer gear.

I suspect that miniaturization of components has a lot to do with the reduction of life. The physically smaller caps seem to handle fewer charge/discharge cycles.

Whitebar:
Are you testing the caps with an ESR meter?
(I only had to replace 3 bad caps in the power supply to repair a unit, and ending up paying double/triple price from Fry's for a quick repair.)

Regards

Whitebar (or anyone),

A bit off topic, but do you also repair other electronics, like a 5 year old Slingbox Pro?

While I know very little about the Slingbox units, a quick google showed failures of bad caps. I am sure I would have no problems with repairs for bad caps or voltage regulators.
Also found there were a lot of failures with the ethernet port. Those would take a lot more reverse engineering and research to repair. I suspect just replacing the defective component would fix the problem but it would suffer the same failure again. I suspect that is due to a design shortcut of not including the recommended ESD/voltage surge protection devices. I have an Denon AVR990 with an ethernet port that was dead after a near lightning strike. I looked at the circuit and there is no ESD/voltage surge protection.

I would take a shot at repairing most items.