[bart_75243]

Greetings from San Antonio,


I'm afraid I've got a huge problem, so thanks in advance if anyone can help.


I'm about 90% done with a year and a half theater build that uses a Sony VPH-1272Q. I built a sealed hush box around it to quiet the noise and have a ventilation circuit to keep things cool.


So here's what happened: last night after watching a movie, I hit the "power down" macro and everything powered off...except for the projector. I woke up this morning and it had been running for about 10 hours without any ventilation. Temperature was 112 F in the box.


I smelled that too-hot electronics smell in the room although the projector still seemed to be working fine (quick picture check). I got the ventilation running again, cooled things down, and powered down the projector. However, hours later it won't come on again. The power-on LED comes on for about a second and then it powers down again, kind of like the fans aren't working.


Does anyone have any suggestions here before I resort to drastic measures? If I absolutely have to, I can get the hush box down to open the chassis. What are the odds I've done irreparable harm to the projector?


Thanks again,

Bart

 

[Curt Palme]

Sure, pull the cover off of the projector. There's a two segment LED display that should flash an error code that will tell you what the problem is.


Let us know!


Curt

 

[Brian Hampton]

Try turning it off for 10 minutes using the hard switch or pulling the plug. Then turn it on just after supplying power.


My LVPS has some intermittant problem and that work around works for me.


-Brian

 

[bart_75243]

Thanks for jumping in on this one Curt and Brian.


I've tried removing power (pulling the plug) for up to 3 hours with no benefit.


Anticipating the error-code query, I went ahead and pulled the hush box down, opened the chasis, and looked for the codes.


Here's the weird part:


Sometimes I get an "11." Other times I'm getting a "19." Occasionally, there's an "E something" that flickers before the code.

 

[bart_75243]

For what it's worth, if I wait awhile between power-on attempts, it seems to be 19 most often.


However, sometimes, I get two codes (E something, something else) followed by no code at all.

 

[windtrader]

I'm suprised the unit doesn't have shutdown circuitry. It has fan speed control, it would seem reasonable for Sony to have built in the shutdown on overheat condition.


Seems like a DIY project in the making to add a hi-temp shutdown sensor.

 

[Brian Hampton]

Hmmm,


I have a power up trouble shooting guide but it's hard to read. One more thing to try.. Turn it off with the hard switch (same as pulling the plug), wait 10 mins, turn it on with the hard switch, press "off" on the remote or on board controller, press "on" on the remote or on board controller. There's a section of the book dedicated to power up problems that require you to use "off" before "on" because of something or other.

 

[Brian Hampton]

Hey,


Here's the guide. Good luck trying to use it. It's advanced and hard to read.


=Brian

 

1270_pwrup_tshoot.pdf 361.7255859375k . file

 

[bart_75243]

Brian,


I did the "off" before "on" thing this morning and still get code 19.


Thanks for the guide...I'll try to decipher it tonight and see whether or not I have a type 2 or type 3 problem.


A quick scan of the guide seemed to indicate that I would need new circuit boards to attempt these diagnostic procedures. Did I read that correctly?


Thanks.

 

[bart_75243]

I've found the Sony service manual and was trying to look up the meaning of the code.


The chart lists:


Code / FAN stop / (H stop)100V down / IK-over / V-stop / HV-over / power-down


and for code 19 has "Y" for FAN stop, V-stop, and HV-over.


What exactly does that tell me and how is this information used in troubleshooting?


Thanks.

 

[bart_75243]

Brian,


You weren't kidding about this guide.


All I can tell you guys so far is that I have a problem of Type 2:


"When depressing the power switch, the power comes ON for an instant, but fails soon thereafter. The same will result even by repeating efforts to get the power ON."


(For those who haven't read the tech note, Type 1 problems are characterized by no power at all, even for an instant. Type 3 problems are identical to Type 2 in that power fails soon after depressing the power switch. However, with Type 3 failures, the power won't come on again before first pressing the OFF button.)

 

[Brian Hampton]

Yeah, that guide is a bit harry. Be carefull trying to use it. I don't know anyone who has used it and I don't know who wrote it. Maybe another member will have some more information on it.


It seems to make sense. I was going through it last night and some of the steps for type 2 (that's the only part I as reading) seem to make perfect sense but it's a scary book and if you want to just wait for Curt to help more instead.. I don't blame you.


Good Luck,


Brian

 

[bart_75243]

For those of you following this thread, here's an update:


I've been deciphering the guide that Brian posted. Having defined things as a Type-2 problem, I started troubleshooting on the PA board.


The first thing I did was to disconnect the HV (high voltage) connectors from the board. There's a hand-written note on the guide that says to disconnect PA 6&8 instead of PA-7. I have the disassembly guide for a 1271 that doesn't map exactly to the 1272 PA board, so I disconnected the three connectors that looked to supply high voltage. There were two on the side furthest from the K board and one toward the middle in the back.


Further on in the guide (pages 8 & 9), there is a section that deals with what to do if removing the HV connectors alone allows power to come on. As such, I tried a power-on at this point. Same shut down after brief power-up attempt.


Moving on, I next disconnected what I believe to be the PA-4 connector. It's the one on the back nearest the K board. This time, when I turn the power on, the projector comes on without shutting down. Per the instructions, I powered the projector down in less than 10 seconds to prevent any damage to the projector.


So now I've narrowed down to a failure of a component that connects through PA-4. According to the guide (page 11), it looks like I've narrowed down to 5 possible culprits:


H Stop protector; V Stop protector; Fan Stop protector; Sigma Ik protector, and the HV protector.


The guide now gives directions for checking each of these protectors. However, I'm not sure if I'm personally up to these checks, so I may see if any of the experts have advice at this point.


Any advice?


I'll post back with any developments.

 

[Kieth]

" I don't know anyone who has used it and I don't know who wrote it. Maybe another member will have some more information on it."


The name at the fax edges seems to confirm a Williams... Not 100% sure, but I believe this was written by Chuck Williams, who used to visit the forum a lot.


Not sure what happened to Chuck - but you can find plenty of fan mod info here from him.


--Kieth

 

[Curt Palme]

I know you emailed me, but I haven't gotten to it yet. This troubleshooting will help though.


The test points are pretty easy, look for them on the various boards.


There are isolation diodes that basically form an 'OR' gate, so that any fault will pull the shutdown high (or low, I can't remember) when a fault occurs. THe key to finding it is to check each diode on the anode side to see which section is causing the shutdown. Let me know what you find, and I"ll get to your email... shortly..


Curt

 

[bart_75243]

As an update to the thread, here's what I just found:


In checking the five protection areas listed in the tech article, the only one that produced interesting results was the fan protection circuit, so I began a thorough check of the fans. Everything looked fine until I removed the power supply to check its fans.


The two fans on the back of the power supply weren't spinning. I looked everything over closely and found that one of the fan lead's insulation had partially melted and was touching the side of the power supply, probably shorting.


I moved the wire so that it didn't touch anything and turned everything on again. The fans powered up, the projector didn't shut down. this one small board (PC) has a power transistor in it, which sparked and smoked. I immediately shut everything down.


This transistor is clipped to the side of the power supply and has three leads back to the PA board (yellow, brown, and red).


So the big question is: did the short from the fan cause the chip to overheat and fail? Could the fix now simply consist of replacing the transistor or this small PC circuit?

 

[bart_75243]

Final (hopefully) update to this thread:


I cross-referenced the power transistor to obtain the NTE equivalent and called around town. Only one of the electronics shops carried the part and it was $28. That's amazingly high for a transistor, but if it fixes the projector, amazingly cheap.


I purchased the part, removed the old transistor from the circuit board and soldered in the new one. The circuit board was then plugged back into the PA board, fingers were crossed, and....success! The projector powered on, and all appeared to be fine.


At this point, the board with the transistor was still hanging in the air, so I proceeded to clip it to the power supply like it had been. Two things were new, however. First: the original transistor had been stuck to the power supply chassis with some thermal tape. It conducts heat but no electricity. This tape is a one-time use thing, so it was damaged when the transistor was removed. To keep the new transistor from physically contacting the metal of the power supply, I used the mica insulator that came with the new part. The second difference was that to help with heat transfer, I used a little cpu compound between the chip and the mica insulator.


Here'e where we take a brief detour. When power is applied again, sparks start to fly. I shut off the power within milliseconds and no permanent damage appeared to be present on the transistor. Either the mica chip wasn't adequate to block the high voltage electricity from the transistor or the cpu compound wasn't completely non-conductive, as I had assumed.


After a trip to the store, I returned with a different insulator pad material (looks like gray silicon rubber) used for transistors and lined the area below and around the transistor. Also, this time I used a heat transfer grease that explicitly stated it was non-conductive.


After making these adjustments, everything powered on and has been running fine since. All the setup has been lost, however, so it's back to convergence to get the picture dialed in again.


Despite the low-cost nature of the final solution, there was a lot of time involved in disassembly, troubleshooting, and reassembly. I hope some of the information in this thread helps others with similar issues. I would certainly never claim to be an electronics expert, but maybe there's something useful in all of this.


Total solution cost: $30 for the transistor, $2 for heat-sink grease, $.50 for insulators, and $10 for a long screwdriver needed to remove the lenses from the tubes.

Total time spent: 10-12 hours spread over a week, including research, diagnostics, and labor.

Also note that I was able to perform all the troubleshooting and work without removing the projector from the ceiling. I did have to remove the lenses to work with the power supply and the PA board, however.


Thanks to Brian and Curt for their advice and willingness to help.

 

[Brian Hampton]

Great. I've been gone all weekend out of town and I'm glad you have it running again.


I have the most unreasonable love for my 1271. Nice to see your back in bussiness.


-Brian