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View Full Version : Any way to test an uninstalled tuner??



ahonamous
01-02-2004, 03:39 PM
I got my hands on a couple of tuners, but I am unsure if they work or not. Is there any (easy) to test the tuners without having to go through the hassle of installing them in a unit? That would really be a pain in the ***. Besides, I am not even sure WHICH tuner I need to replace...

Thanks,
Anne

GREEK
01-04-2004, 07:36 PM
theres no sure fire way to test them really. The real way is to have a known working tuner, and then pin out from the ground pin and the 2.5 input to all the other pins and record the #s. Anything more than 15% difference is suspect usually. Whay you wanna do is pop off 1 tuner at a time, and then resolder only the tiny pins, not the 4 outer hold legs of the tuner shell. If you visually inspect the QSPK chip, you may find a visible flaw in it. Also the first red cap on the front lower of the tuner often goes too. What signal scenario do you have. Missing even or odd xponders is a lnbp chip usually, no signal at all may be low 30v line, easy to check, and getting stuck at almost there could be alot of things. Make sure you need a tuner for sure b4 you start, and do #1 first and then test, dont take both off, you wont know which is bad..........

ahonamous
01-05-2004, 08:43 PM
theres no sure fire way to test them really. The real way is to have a known working tuner, and then pin out from the ground pin and the 2.5 input to all the other pins and record the #s. Anything more than 15% difference is suspect usually. Whay you wanna do is pop off 1 tuner at a time, and then resolder only the tiny pins, not the 4 outer hold legs of the tuner shell. If you visually inspect the QSPK chip, you may find a visible flaw in it. Also the first red cap on the front lower of the tuner often goes too. What signal scenario do you have. Missing even or odd xponders is a lnbp chip usually, no signal at all may be low 30v line, easy to check, and getting stuck at almost there could be alot of things. Make sure you need a tuner for sure b4 you start, and do #1 first and then test, dont take both off, you wont know which is bad..........


Well, I have been exchanging PM with cali.. He was kind enough to perform an initial diagnosis that I have a bad tuner. I just don't want to go through the hassle of installing an unknown tuner when it is bad.

Incidentally, if I remove a bad tuner 1 and leave in a good tuner 2, am I correct in understanding that I will get past the "Almost there..." screen, even though I have no tuner 1?

Thanks,
Anne

GREEK
01-06-2004, 02:49 AM
yes you are correct. any time a part is holding down the IC2 bus it will free the line when removed. This is true for ground shorts and components shorts. Basically, both tuners, both lnbp chips, and all five of the "big chips" on the board will hold down the line if bad. Also U13 will as well, the tuners and chips are easiest to remove, then comes the modemcontroller at u13. You should realisticly only do one part at a time, thus knowing when the bad part is found. The crappy thing is 90% of the time, a bad tuner takes out a chip too, and often both tuners go when its a surge or lightning hit, and both tuners were enabled. I'm sure he told you this as well. grab a desoldering iron at ratshack, makes life alot easier for 7 bucks......

edit: you can test pin 7 resistance with a voltmeter, but its not a good way afaik. There are 3 trouble spots on tuners, and I have working tuners with a low reading on this pin........

ahonamous
01-06-2004, 09:19 AM
yes you are correct. any time a part is holding down the IC2 bus it will free the line when removed. This is true for ground shorts and components shorts. Basically, both tuners, both lnbp chips, and all five of the "big chips" on the board will hold down the line if bad. Also U13 will as well, the tuners and chips are easiest to remove, then comes the modemcontroller at u13. You should realisticly only do one part at a time, thus knowing when the bad part is found. The crappy thing is 90% of the time, a bad tuner takes out a chip too, and often both tuners go when its a surge or lightning hit, and both tuners were enabled. I'm sure he told you this as well. grab a desoldering iron at ratshack, makes life alot easier for 7 bucks......

edit: you can test pin 7 resistance with a voltmeter, but its not a good way afaik. There are 3 trouble spots on tuners, and I have working tuners with a low reading on this pin........

I was hoping I could simply de-solder the power pin to the tuner as opposed to completely removing it (cali recommended pin 22). But it sounds like this may be a real task.. If I pull out tuner 1 and still have a problem, tuner 1 (amongst other things) could still be damaged.. It sounds like I just start removing until I get something to happen, then start to slowly re-install them to see if things still work...

I will remove tuner 1, if I still have a problem, would you recommend removing tuner 2 next or the chip (I assume you mean lnbp)?

Anne

cali
01-10-2004, 08:55 AM
Hey Anne,

its been a while...I though u got yourself fixed. I kinda skimmed thru the thread.

What greek is saying is best, I'm pretty confident its a tuner, but you will HAVE to take em out one at a time.

The pin I told you is the 3.3V Line. If you measure that to groudn you will get a very good reference to determine if the tuner is bad. The QSPK go bad 95% of the time on these things. A good way of knowing if a component is defective is to also cool/heat it while checking its resistance. You ill see major fluctuations if its bad, esp on the QSPK's.

You have to , no matter what, remove the tuners one at a time. Start with #1. If I recall, we already established that it wasnt the modem causing the hang.

Cali

ahonamous
01-11-2004, 12:04 AM
Hey Anne,

its been a while...I though u got yourself fixed. I kinda skimmed thru the thread.

What greek is saying is best, I'm pretty confident its a tuner, but you will HAVE to take em out one at a time.

The pin I told you is the 3.3V Line. If you measure that to groudn you will get a very good reference to determine if the tuner is bad. The QSPK go bad 95% of the time on these things. A good way of knowing if a component is defective is to also cool/heat it while checking its resistance. You ill see major fluctuations if its bad, esp on the QSPK's.

Cali

Cali-Good to hear from you.. I put the project aside because I had no time, but its back out now..

While trying to figure out what to do, I opened my eyes and saw that pins 1 and 2 of LNBP U37 were fried. Everything I am reading indicates that when an LNBP is bad, so is the tuner. Knowing that, I felt very confident in pulling out tuner 1. I did so and have yet to test it--again not enough time. I also decided I might as well pull out the LNBP. Well, desoldering the pins of the LNBP with some desolder braid was easy, but that dang chip is held down to the board somehow. This all now leads me to 2 questions..

1. Anyone know how to safely remove the actual LNBP chip from the board without blowing anything else up?

2. With a dead LNBP, and most likely the tuner, what else typically blows when the LNBP goes bad?

Thanks,
Anne

sfg
01-11-2004, 07:24 PM
I might be able to follow some of these tips if its for HDVR2.

Thanks
sfg

GREEK
01-11-2004, 08:36 PM
were talking ser1 here, not ser2. Post what the problem is in the thread you started, its a different ballgame with those.........

sfg
01-11-2004, 08:40 PM
OK

thanks
sfg

GREEK
01-12-2004, 03:12 AM
Sorry, didnt realize you posted back. The lnbp chip is held down with solder, you need to heat it up to get it off. A hot air pencil or a heat gun/blow drier may work if you can focus the heat. You must be careful though, the other caps and stuff near it will get hot and move if you shake the board. I have heard of people doing this way, but I personally would really be sure I had the heat focused before even thinking about it. You should be good to go, if the lnbp chip is off and the tuner out you should boot up. You could snip the legs and leave a large gap to the lnbp chip body and just leave on there for now to get it booting. Once you have the unit booting, your gonna need someway to get it off and another installed, a local shop should do it for 10 or less, maybe a favor if you smile and say please, it takes 30 seconds on and off included..........

cali
01-12-2004, 07:38 AM
Again to re-iterate what the greek is saying,

If you have tuner 1 out, YOUR SYSTEM SHOULD BOOT up to the guide acquisition screen, if tuner 1 is defective. If it still hangs pull out tuner #2. I have seen stranger things.

As to removing the LNBP chip from the "heatsink" on the PCB. Two irons work well in this case too....If I dont have the pencil nearby, I put the big gun on one side and the 20W on the other....5 Secs later I launch the chip into orbit :D

GREEK
01-13-2004, 03:40 AM
exactly what cali said. the only caveat is most lnbp chips I see around here are ALREADY launched into outer space, kinda like a rod going through the hood :D

ahonamous
01-13-2004, 02:25 PM
Some success...

First, I tried the system with Tuner 1 removed and lnbp pins cut. With hard drive one, it booted to "almost there... A few more seconds" or something like it. It then rebooted itself twice and then started to reboot at the "Powering up screen". I figured I had a bad image, so I tried hard drive 2. It would keep restarting at "Powering up" and after 4 or 5 times the hard drives stoppeed spinning up. I was sure I blew the power supply somehow. I tried Drive 1 again, just to be sure and BINGO. It started up, game me the "Phillips Presents" Screen and then the Tivo-guy with the 0% downloading database info. I stopped it at that point (I did not have it hooked up to the sat input at this point). I have no clue what was up with the hard drives--it was probably a ROM flash that was in there (it has been a while since I played with the image). I installed a new Tuner 1 and right away got to the "Phillips Presents" screen.

Next step... the lnbp. I took Greek's advice and brought it to a TV repair shop. The guy hemmed and hawed about him doing the repair and that I should not be playing with a circuit board, but he had his guy pop off the lnbp. It did take him a bit longer than Greek's estimate of 30 seconds--it took about 38 seconds. :)

Tonight, the adventure continues when I install a new lnbp.

So far, a HUGE WHOPPING thanks to both CALI and GREEK.. I could not have gotten this far without either of their input!!

Anne

GREEK
01-13-2004, 08:04 PM
Congradulations on the success. Feels good to fix yourself huh? I will add that you should be careful with the tuners you stick in. I always just do the pins, not the 4 outer retaining pins. Makes life easier if the tuner is questionable, I think you stated you were unsure where they came from. A bad tuner may or may not hold up the tivo, it depends on the way it died and where its bad. You can use an iron to pop the legs on, then a little touch of soder on the sides just to help secure the chip, but as long as the legs are on good your OK. Be careful NOT to have ANY solder bridging the gaps. Legs 2+3 (24v & 13/18v) touching will fry your machine. I have personally thought the legs were solid and under magnification one was not, it'll drive you nuts. I would definitely test the supply outages on the unit. The majority of times you have a reboot of some sort is unstability in the output. It doesnt matter if drives work in another unit, the jumpers may need to be adjusted and the voltage tweaked a little. They usually come out of whack, a voltmeter and the orange pot screw is easy to do. Just move a tiny bit when adjusting. If you make it to almost there and it reboots its not the prom flashing. Only when it sits there for 30 seconds and reflashes upon 2.5 install is when its happening, otherwise its the unit shutting down. If you know you have a good lnbp chip on there and you have signal problems, swap tuners til you find a good one. Post if you need any help, I'm glad you've come this far...........

cali
01-14-2004, 09:54 AM
Some success...

First, I tried the system with Tuner 1 removed and lnbp pins cut. With hard drive one, it booted to "almost there... A few more seconds" or something like it. It then rebooted itself twice and then started to reboot at the "Powering up screen". I figured I had a bad image, so I tried hard drive 2. It would keep restarting at "Powering up" and after 4 or 5 times the hard drives stoppeed spinning up. I was sure I blew the power supply somehow. I tried Drive 1 again, just to be sure and BINGO. It started up, game me the "Phillips Presents" Screen and then the Tivo-guy with the 0% downloading database info. I stopped it at that point (I did not have it hooked up to the sat input at this point). I have no clue what was up with the hard drives--it was probably a ROM flash that was in there (it has been a while since I played with the image). I installed a new Tuner 1 and right away got to the "Phillips Presents" screen.

Next step... the lnbp. I took Greek's advice and brought it to a TV repair shop. The guy hemmed and hawed about him doing the repair and that I should not be playing with a circuit board, but he had his guy pop off the lnbp. It did take him a bit longer than Greek's estimate of 30 seconds--it took about 38 seconds. :)

Tonight, the adventure continues when I install a new lnbp.

So far, a HUGE WHOPPING thanks to both CALI and GREEK.. I could not have gotten this far without either of their input!!

Anne


Good job.....finaly grew some balls huh :D :)
Hope you have a good replacement tuner ;)