Trinitron KD-36FS130 sudden issues - Videokarma.org TV - Video

YamahaFreak · #1 02-28-2021, 09:47 PM

This set was working great for months until yesterday when someone finally agreed to buy it...just my luck, right?? Sometimes it powers up, sometimes it doesn't. When it doesn't, I get degauss and about 3 seconds of HV before it shuts down and throws a 5-blink timer LED code. Google seems a bit vague on this, with no specific incidences of this issue on my model. This TV has an onboard digital tuner, and it, along with the video inputs (at least the component inputs) were also not working just prior to the issue beginning. I had the set unplugged since yesterday and when I went out and plugged it in tonight, it started up...but still without any inputs or really anything other than the onscreen menu. Powered it off and back on, and I get the shutdown and 5 blinks again. This one has me stumped! It's been stored indoors and not moved for months, nothing changed about it or its storage conditions between then and now.

Also worth noting is that when it was working properly, the menu settings would all be reset every time it was turned off, regardless of if it was unplugged or not. Bass, treble, picture controls, all reset...and the built-in speakers are also turned off by default, which I found strange. It even loses the PIN for the parental controls when powered off, as if the PIN was never set up.

zeno · #2 03-01-2021, 04:35 PM

I dont remember 5 blinks but most Sony shut down problems
are cold joints at the vertical out IC & at the horz drive transformer.
Other reasons I remember are: no vert, too much HV, Horz over current,
failure to achieve acceptable grey scale & a few more.
As far as the default problem goes you probably wont find it. Something
like that will send a tech running for the door. For a few years you could
get whole boards for something like that but they are soon gone or
sold off as scrap.
Oh has anyone been in the service menus ????

73 Zeno

LFOD !

YamahaFreak · #3 03-02-2021, 08:39 PM

I found this, as far as 5 LED blinks.

Five blinks - AKB circuit (automatic kine bias), the timer/standby indicator blinks for about 30 seconds then goes to the self-diagnosis function. Something is wrong with the video. Check video out, Q705, 732, 761 and other components on the C board, also check Q218, 219, 220 on the A board. In addition, unit could be in IK blanking, try turning up screen slightly.

I don't think IK blanking is the issue, because when it DOES come up, the CRT looks perfectly fine. I think the issue is time-based, i.e. the set will not power up if I try turning it back on if it has previously been on within the past 24 hours or so. There is also nearly no delay or blinking prior to the error code being thrown; as mentioned, about 3 seconds in and it shuts down.

zeno · #4 03-05-2021, 04:25 PM

Every AKB problem I have seen ( many) was a weak CRT. On
older sets this caused blinking that slows with warm up. When it
does its obvious the CRT is weak. It did not cause shutdown.
One thing may be a H-K short. If it runs a while try lightly tapping the
CRT neck & see if it craps out. This was on older sets.

The other thing is the power supply. Not sure what yours has but the
wide screen ( 30" & 34" ) sets had 2 IC's that constantly go. They caused
all kinds of problems related to dead set, int start, shut down, hard start.
More on that if needed. I had one & got sick of changing them
every year. Other than that they were probably the BEST CRT TV ever
made.

73 Zeno

LFOD !

YamahaFreak · #5 03-08-2021, 02:13 AM

Quote:

Originally Posted by zeno

Every AKB problem I have seen ( many) was a weak CRT. On
older sets this caused blinking that slows with warm up. When it
does its obvious the CRT is weak. It did not cause shutdown.
One thing may be a H-K short. If it runs a while try lightly tapping the
CRT neck & see if it craps out. This was on older sets.

The other thing is the power supply. Not sure what yours has but the
wide screen ( 30" & 34" ) sets had 2 IC's that constantly go. They caused
all kinds of problems related to dead set, int start, shut down, hard start.
More on that if needed. I had one & got sick of changing them
every year. Other than that they were probably the BEST CRT TV ever
made.

73 Zeno

LFOD !

I do know it's not a weak CRT, as I have a KV-27S25 in the back waiting for a tube swap that exhibits those exact symptoms. (Flashing for a while before finally coming up, and seriously out of whack colors and convergence on the CRT) The 36" one looked perfect before it decided to start wigging out. I have heard of the MCZ chips on the power supplies dying...I suppose that could be the issue, though I hope not, as I'm garbage at soldering those large ICs. I really wish they'd put them in sockets!! I have a 32-inch flat screen Trinitron that needs one of those chips. (Some models have a pair of these ICs)

JohnCT · #6 03-08-2021, 06:38 AM

My notes show that this chassis does use the MCZ3001 chip. Since the original Shindengen chips became temperature sensitive in most of the cases, a good way to check is to preheat the IC before turning the TV on. If it starts every time with the chip preheated, it's bad. If the TV starts most of the time but only fails to start occasionally, you can cool the chip first. If the problem gets worse, the chip is bad.

The bad news isn't changing the chip, the bad news is that originals are scarce. Unfortunately, there are a lot of counterfeit MCZ chips out there, and they not only won't work, but will sometimes trash parts around it. The last place I knew that had originals was B&D.

John

Electronic M · #7 03-09-2021, 09:23 PM

Quote:

Originally Posted by YamahaFreak

I do know it's not a weak CRT, as I have a KV-27S25 in the back waiting for a tube swap that exhibits those exact symptoms. (Flashing for a while before finally coming up, and seriously out of whack colors and convergence on the CRT) The 36" one looked perfect before it decided to start wigging out. I have heard of the MCZ chips on the power supplies dying...I suppose that could be the issue, though I hope not, as I'm garbage at soldering those large ICs. I really wish they'd put them in sockets!! I have a 32-inch flat screen Trinitron that needs one of those chips. (Some models have a pair of these ICs)

They are (IIRC 18 pin) DIP chips. Just buy a DIP socket with the correct number of pins and install the socket, then once the socket is soldered pop the chip in. I'm not the best at soldering PCBs either and I did just that (I did use a spring plunger type solder sucker)...I also added a heat sink and in the 2-3 years since the MCZ I changed hasn't failed...the other MCZ (my set uses 2 of them) hasn't failed yet (knock on wood).

I think I also solved what I believe was an intermittent heater cathode short issue last week. What I did was measure heater voltage and current, disconnect the socket heater terminals from the PCB and connected a small 6V relay that draws less current than the 6.3V 450ma heater and used that relay to switch on and off a new floating heater power supply I built from a 120V to 12V stepdown transformer a bridge rectifier and a LM317 regulator circuit (configured to output 6.3V). I also connected the heater to ground through a 1M resistor and .05uF cap to bleed charge down and ground any AC noise. Before this the set would have grayscale disturbance followed by it going red screen (with retrace lines) and triggering an automatic shutdown....in the week since it has only had 1-2 grayscale disturbances that have fixed themselves.