DSR-922 Capacitor Replacement

Alan's Satellite Page Alans DSR-922 Battery instructions Alan's DSR-920 Battery instructions VCII Battery Replacement Instructions

 

The following DSR-922 Capacitor replacement instructions and are intended for folks that are comfortable soldering electronic components without shorting out their expensive 4DTV receiver, or blowing up the volatile Lithium battery, causing injury, and damage. Please read my old VC Battery page for important tips, and warnings. Don't try this procedure If you are not comfortable doing this type of stuff. Don't cry to me if you loose your DCII ID number or ruin the whole main board.

I dont recommend this procedure unless you confirm AC component on the dc regulators noted. ATS can repair your DSR-922. There are potential lethal voltages present, and you could destroy your receiver easily.

I bought my first DSR-922 six months after they first came out. After about seven years use I started noticing occasional digital picture dropout, with high quality signal (70 to 99 qualities) the first test I did was to check alignment and connections.

I tested the suspect receiver against another one of my 4DTV receivers, split the LNB input off the same dish, tuned to the same digital channel. This confirmed that my oldest receiver was the culprit. Most of you reading this dont have a capacitor problem, dont jump the gun, most breakup problems are receive site problems. They usually arent caused by a faulty receiver, or the bazillion dollar satellite that you might think has got a short. Most of the time it is dish alignment, obstruction, damage, or inadequate size to null out the blasting signals from the adjacent 2 degree spaced satellites screaming at your dish on either side. Try to picture three people standing in front of you. They are talking loudly, you want to only hear the one the middle. The more you can cup your ears the better you can hear the intended conversation. Parabolic reflectors can focus energy like a magnifying glass focuses light on an ant. Dishes that are less than ten foot are usually unable to null out enough adjacent noise from two degree spaced satellites.

My problem only effected digital channels, the higher symbol rates (SR) were worse when the problem happened. Sometimes I could only get lock on SR 9.76 channels like G-0 125.  It seamed to breakup more in the morning, sometimes it would not lock at all for hours. If youre having similar receive problems, switch to G-0 125, then go to the hidden diagnostics screen C, press remote buttons (options 6 0 5 > > Help) The help button creates a macro so you can go directly to the diagnostics C screen in the future, now press (exit) look at screen, then press (help) only once. Bam, youre there! On Diagnostics C (*=help macro)

If you have signal lock, the top left will display 07, no lock display 04 to the right of that is 8 digits starting with 000 then numbers and alphas. This number shouldnt change once locked. If it changes, youre throwing BUR errors (receiver is loosing data) The next line down shows how cheap your LNB is, if it is +/- 2.000 youre a cheap bastard, just joking :-) Its actually the frequency error of your LNB, or maps. The next tidbit to the right of the freq error is the symbol rate (SR) 9.76, 19.51, or 29.27.  The normal Diagnostic C top left will look like this on G-0 125:

07 000123AB (07 is signal lock, no numbers changes once locked

-4.375 9.76 (Line 2 freq error -4.375MHZ  freq changes once locked show unstable LNB, SR is 9.76) (FYI G-0 125 is mapped off frequency about -4.5Mhz)

 

When my receiver was having problems it would not lock at all, or lock 07 then unlock 04 over and over randomly every few seconds. The 8 digit Reed Solomon error count would change, indicating massive loss of data. When it was locked my quality was normal 70 to 99. When tuning digital signals ignore signal strength, the quality once above 14 is all that matters. Signal quality is based on error counts, the count reacts slowly on the 922, it may take 10 seconds to settle down to an accurate number. Always peak stored satellites on digital channels, when available. I dont use the signal strength meter at all, remember the three people screaming analogy? There is your signal strength. (Click here for more tuning tips).

Most of these symptoms will also show up with a receive site problem, the subtle differences I had were normal quality when it was locked, and the ability to lock 9.76 SR channels when higher SR rates wouldnt lock at all. Then after sitting on the 9.76 for a while the 19.51, and 29.27 channels would start to lock too. Learn more about the Diagnostic C screen here

The main board must be removed to gain access to the bottom of the PCB

 

DSR-922 Cap replacement

 

Note the darkening of the board near the 4 regulators in front of the arrow all of those caps were suspect. Prolonged excessive heat can dry out electrolytic capacitors.

 

 

This was the location of the bad cap on my board; the others to the left (towards the back connectors) should be checked for oscillations too. (Watch my cap check video instructions HERE)  The original part was a 16v 22uf cap. I replaced with the green 35v 22uf high temp cap shown. Replacing the cap was not easy, even with a professional powered solder sucker. The PCB is thick; the ground hole was hard to suck clear of solder.

Probing around on a hot board is dangerous; if you dont do this stuff regularly, hire someone that does. There are potentially lethal voltages on the motor board, up front behind the display, and on the power supply board. If you short out a probe it could kill the receiver, or you. Check for AC with a VOM set to AC on the millivolt range, or if you have one use a scope. A scope should show a straight line, no ripple. Any reading above several millivolts is suspect. Look at this 922 HIGH VOLTAGE WARNING VIDEO

Some compatible high temp electrolytic capacitors: http://products.nichicon.co.jp/en/pdf/XJA043/e-vr.pdf

I recommend you buy a new battery and several electrolytic caps before disassembly. The board has many 10uf 16v and the one I found bad was a 22uf 16v. Use a can of compressed air to clean the dust bunnies out, read my VCII instructions for important warnings and recommendations. Bad caps on the power supply board could cause similar problems to digital and analog reception. If you havent done a lot of PC board repair please contact ATS for professional DSR-922 repair, they have great service and rates. Many folks get there receiver repaired and returned for under $150.

ATS-Electronics.com   Check with ATS for a price on replacing the battery, or main board.

Mouser or Digikey have replacement batteries and electrolytic capacitors

  Battery TL-5955/P, Electrolytic capacitors rated minimum: 85 Celsius, 16 volt, 10uf and 22uf

 

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