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| "fred" <fred002@no.net>: Nov 04 08:29PM -0500 The HDMI port on my Motorola DCT6416 suddenly stopped working. The composite Video still works ok. Searching for HDMI failure on that model comes up with plenty of hits (seems to be a common problem), but I cannot find anything on what the exact component(s) are that fail. I opened it up and checked for any visible problem, but didn't see anything obvious. Has anyone dealt with these DVRs or can provide any idea of what's involved, or if it is even worthwhile trying to get it fixed? Thanks |
| John-Del <ohger1s@aol.com>: Nov 05 04:44AM -0800 On Tuesday, November 4, 2014 8:27:51 PM UTC-5, fred wrote: > anything obvious. > Has anyone dealt with these DVRs or can provide any idea of what's > involved, or if it is even worthwhile trying to get it fixed? Thanks Most HDMI failures are either from corrupted firmware or a bad HDMI transceiver chip. Follow the fine foil lines from the HDMI jack to an IC. Get the number off it and check on line for the datasheet. That's what usually causes the problem. HDMI ports are notorious for being whacked by lightning hits, and it doesn't take much. |
| "fred" <fred002@no.net>: Nov 05 11:32AM -0500 > IC. Get the number off it and check on line for the datasheet. > That's what usually causes the problem. HDMI ports are notorious for > being whacked by lightning hits, and it doesn't take much. The DVR menu says HDMI ENABLED, but not ACTIVE. The re-activation didn't help, and my cable provider couldn't (or wouldn't) tell me where they get their rented DVRs repaired. Since I own the box, I phoned around for estimates, but none had ever fixed any of these, and so they told me that the repair cost would likely be higher than buying a new one. If I knew for sure that a particular chip was defective, I would probably try replacing it myself, but I think it makes more cost-efficient sense to just get another one. Appreciate your reply. |
| sonnichjensen@gmail.com: Nov 04 11:08AM -0800 > You mean missing red ? Well, I have seen blue shades now and then, but right now I dont. only green. > Cathode voltages. If the red cathode voltage is higher, it is in the circuitry. If it is lower it is the CRT. RGB are DC: 76 - 68 - 72V By scope: 60-100, 45-95, 60-100 According to your theory the CRT is then ok. There are only a few other pins in use - 2 grounded, one has 135V (some grid I guess) and one more which reads 0 (filament on AC?) And focus of course. > It is less likely for the color decoder to cause the loss of a color than something in the video output circuitry, usually mounted on a board right on the CRT socket. That is the main place to check. If you do not have information on it, you can see there ar three identical things going to three of the pins. Those will be the cathodes. You should see eacj go through a resistor or sometning to a pin on an IC or transistor. If there are three ICs you can swap them to ind the fault, but alot of them use one IC for all colors. Or it could have three transistors. If you can get a good picture of the CRT board (where the socket is), I can probably sort out what's what if you don't do well at reverse engineering. The TDA3565 is mounted in the base board, which 3 wires to the transistors on the CRT board - they were C2229 but not are NTE287. Both the TDA3563 and transistors are replaced with new ones. I wonder how I can turn off the green to see if I have any other colour WBR Sonnich |
| dansabrservices@yahoo.com: Nov 04 11:24AM -0800 > The TDA3565 is mounted in the base board, which 3 wires to the transistors on the CRT board - they were C2229 but not are NTE287. Both the TDA3563 and transistors are replaced with new ones. The on-line cross reference has NTE399 as the replacement for a 2SC2229. While the characteristics are similar in many cases, I would use the corerct sub first. Dan |
| "William Sommerwerck" <grizzledgeezer@comcast.net>: Nov 04 02:41PM -0800 > I wonder how I can turn off the green to see if I have any other colour. Got a soldering iron? |
| jurb6006@gmail.com: Nov 04 04:35PM -0800 >"RGB are DC: 76 - 68 - 72V By scope: 60-100, 45-95, 60-100 According to your theory the CRT is then ok. " Not necessarily. I as expecting to see the red cathode alot higher. Since you have dicrete video outputs and not a chip you can clip lead test it. Turn your brightness/cpntrasdty down and tak a 10 K resistor from the red cathode to ground. You should see red. Use a voltmeter and make sure the 10 K is pulling the red cathode voltage down below the other two. Once you see red get it off of there, in fact just stick the resistor in the end of a grounded clip lead. Use the connection to the CRT aquadag for a ground because we haven't determined what kind of power supply this thing has. Is might not be totally isolated, and you don't want to use the hot ground. If the 10 K doesn't pull it down to like 50 volts, try maybe an 8.2 K. Only connect this temporarily as it might result in excessive cathode current. Once you see the color that is enough. In fact go ahead and try the blue as well. Once the CRT is actually confirmed good, then it is a matter of working backwards. |
| jurb6006@gmail.com: Nov 04 04:37PM -0800 Reason for the cliplead test is because CRTs are not created equal, and neither are the three guns or phosphors in one. Some seem to swing to full on with like a 30 volt drop, others take 100. |
| Tim R <timothy42b@aol.com>: Nov 04 10:44AM -0800 On Wednesday, October 29, 2014 10:23:21 PM UTC-4, micky wrote: > Not 101.1. 90.1, C-Span radio, which I guess I've lost interest in. > It's boring as all get out during the committee hearings, and the 7AM > program used to be great, but it's been discovered by the wackos. I can't stand C-span though they have some good programming. The problem is that fake synthesized brass keyboard they use for the theme music. How hard would it have been to buy a CD of a real brass ensemble playing it? That piece has been recorded many times. |
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