1. The PHILCO Phorum
  2. Philco Radio Discussions
  3. Philco Electronic Restoration

Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Threaded Mode
Restoration of a digital to analog converter box
wa2ise
Member
***
Posts: 77
Threads: 24
Joined: Nov 2010
City: Oradell, NJ
#1

03-18-2020, 04:41 PM
This is about fixing a bad set top converter box, for your Philco TV set. 

I had a dead Channel Master CM7000 HDTV to NTSC analog converter box.  Its red pilot light, usually an indicator that lights during a boot-up after plugging this box to the powerline, never went to green or orange (indicating it is ready for the user)

As is usual with electronics made recently, it had bad leaded electrolytic caps.  Googled "dead CM7000" and found this thread: https://www.avsforum.com/forum/27-replay...st59384596

I already tested the power supply by using it to power the "logic" board in another CM7000, and it worked.  So the problem is in the dead box's "logic" board.  I got joy   Icon_smile after changing caps E5 and E6 (as marked on the circuit board).  These caps are filters on switching DC-DC voltage converters, going from 5V (or is it 12V) to 3.3V and a second circuit 1.2V.
Website Find
morzh
Odobenus rosmarus
******
Posts: 16,476
Threads: 573
Joined: Oct 2011
City: Jackson State, Province, Country: NJ
#2

03-18-2020, 05:00 PM
Who made the caps and what kind?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Find
wa2ise
Member
***
Posts: 77
Threads: 24
Joined: Nov 2010
City: Oradell, NJ
#3

03-19-2020, 03:07 PM
I tossed them in the trash, I took a look to see if I could find them, but couldn't find them.  They were some no-name brand of aluminum leaded electrolytic cap made of Chineseium...
(This post was last modified: 03-19-2020, 03:08 PM by wa2ise.)
Website Find
« Next Oldest | Next Newest »
Thread Closed




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM
Zenith H725
Ed; One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to ...Arran — 11:42 PM
Zenith H725
I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. Th...EdHolland — 08:39 PM
Zenith H725
The PSU filter cap arrived today (thank you USPS!) so I will work on that later. Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM
The list of my radio & TV collection!
Magical chords of forgotten melodies, old nostalgic music on an old radio... Saturday night blues on the Mid-Waves on an...RadioSvit — 12:20 PM
Philco 42-345 Restoration/Repair
Thank you MrFixr55 the issue with this radio is that the internal coil antenna is missing and there was a wire in its pl...osanders0311 — 11:34 AM
Philco 610B oscillator wiring
Regarding the oscillator circuit which is comprised of the 6A7's cathode, control grid, and screen grid. These elements ...Radioroslyn — 10:33 AM
Philco 42-345 Restoration/Repair
Hi OSanders, First off, welcome to the Philco Phorum where Phine Phamily-Phriendly Pholks Phull of Philco Phacts and P...MrFixr55 — 08:41 AM
Philco 42-345 Restoration/Repair
Today I've been reading through the site trying to learn more about this radio. I also soldered the lose power cord cabl...osanders0311 — 08:24 PM

[-]
Who's Online
There are currently 2406 online users. [Complete List]
» 1 Member(s) | 2405 Guest(s)
Avatar

>
  1. The PHILCO Phorum
  2. Philco Radio Discussions
  3. Philco Electronic Restoration