Any idea what monitor symptom this is? (K7000)

[danielm7999]

Got any ideas why this happened after installing a new H.O.T. / voltage regulator /and  B+ filter cap? Is this vertical collapse?



- when I change the "v-size"

Before changing these 3 things my picture was ok...but I was previously having other issues so I decided to change out the 3 things listed above. I recently did a cap kit and changed the flyback a few months before changing these 3 things today. Not sure why this wouldve happened suddenly today. Any ideas?

Thanks

[grantspain]

have you tried vertical hold and position pots yet

[danielm7999]

Yeah definitely...I even tried adjusting the 50/60hz pot on the board.

With a new HOT, voltage regulator, and B+ filter cap I checked the B+ readings and got around 40v.

So when I tried putting the old voltage regulator back on the chassis I got a B+ reading of about 52v

Then, with the old voltage regulator back on the chassis, I put the old filter cap back on and got a reading of about 54v. I havent put the old H.O.T. back on but Im guessing it wont any difference.

I didnt have this screen problem before I originally added these 3 new parts. Now with 2 out of 3 old parts back on, my screen is still messed up.

[ed12]

40 volts on the req. ?

ed

[grantspain]

none of those components should cause that issue
the voltages you read are not correct but i suspect you are reading them incorrectly as 54v would not even run the chassis
if its a 14-19" chassis then you should get 123v dc for b+(c57)

thats looks more sync related although i have seen vertical deflection ic faults  cause some oddball conditions

do you have a standard jamma board you can use as a test signal

[danielm7999]

I was measuring B+ on this device (see pic). It is a 25" T2 cabinet

I did a cap kit a while back and noticed that C57 cap had blown and was leaking brown fluid onto the board. I changed that cap, but wondering if that blown cap would have weakened anything else...like the IC? When I first got the game the original monitor was VERY dim. I put a new monitor in it and got the picture back to perfect after a cap kit and flyback change. Once in a while the picture would flash and switch to a slightly smaller picture, then switch back to normal again after a few seconds. This didnt happen very often though....but I decided to change out the HOT/voltage regulator/filter cap(C55) in hopes to eliminate it. Afterwards I ended up with this current issue thats seen in the video links above.

Again, this current issue with my monitor didnt happen until I switched the HOT/voltage regulator/filter cap(C55). So I'm guessing that changing those may have shorted something else, like one of the old original parts. Maybe the IC?

I will check into getting a correct B+ reading...I guess Im doing it incorrectly.

Thanks

[grantspain]

ok then the b+ should be 130vdc-the regulator should be a str30130 or equivalent

you can read the b+ at the 220ohm resistor for ease,use the heat shield of the flyback for ground-meter set to 200vdc range

you should also check c48

[danielm7999]

Ok thanks. Im new to this voltage stuff so I was measuring it wrong. Still clueless on getting this fixed after another day of testing it, but here are the specs Ive gathered so far:

B+ reading was 161.9 on one terminal of the 180ohm resistor (seen in pic) and 120.2 on the other terminal of that same resistor. Thats with the new voltage regulator installed (and yes, its a 30130).
With the OLD original 30130 regulator, the B+ measured 161.3 on one side and 107.3 on the other side

The resistor Im measuring from on the side of the chassis has "180ohm" printed on the side of it. I measured its ohm's AFTER I pulled it OUT of circuit and got 179.6, so that resistor is good.

I will check c48 tonight.

[ed12]

the str is working 130 is the very good out
120 means u have some thing loading it in the b+ path
did u pull the vertical ic yet ?
as that will put a load like that on the reg.

ed

[danielm7999]

Thx,
I did not touch or pull the vertical IC out at all. And the regulator is brand new.

When I did a cap kit on this (maybe 6 months ago) I bought from Bob Roberts. Im hearing his caps arent very good quality (not to knock the guy - he seemed very cool!). Should I buy better caps and swap them out for starters? After doing all kinds of homework on this Im running out of ideas. Other than swapping out the IC's...but I guess its a bad idea to throw more new parts at this thing if Im uncertain.

Ive attached a side by side pic of the chassis board front & back if that'll help solve anything. Someone before me soldered in a wire trace in 2 spots that had the traces burned. But the continuity is good on those makeshift traces. And like I said, the game was working fine for about 5 months without much issue, other than an occasional quick 1 second screen flash. Eventually that screen flash kinda became more frequent so I decided to try changing out the HOT/regulator/and B+ filter cap...which is what got me the current screen symptoms I'm posting about ( )

Heres an HD overview of the bottom of the chassis:

[ed12]

na 90% of that looks like factory mods
your problem still lays in the b+ path
do u have a schmeatic for it ?
if so follow the path to find the draw
if u are having problems trying to understand let us know we will guide u

ed

[danielm7999]

Would this be the correct schematic? I believe mine is a 7191, if I remember correctly (it's late).
Man this one is all Greek to me, but I suppose if I need to learn it I will.

[ed12]

look for q9 to be leaky
or look at pin 6 of the vert ic for +12v

ed

[danielm7999]

Okay thanks I'll look for "q9", although I havent found anything leaky across the board. For testing the vertical IC pin 6 I dont have to pull it out of circuit do I?

Not sure if this gives any hints at the possible issue, but when I adjust the V Hold pot absolutely nothing happens.  No changes in the screen image at all whatsoever (V Hold pot was working very recently before this issue came up so Im pretty sure the pot is good). H Hold will move the screen from side to side. Other pots also make changes of course, but nothing fixes it. V Hold is the only pot that doesnt makes no difference whatsoever. So Im wondering if thats a sign that the vert IC needs to be replaced. Im a rookie at this so maybe thats a retarded guess.

[behrmr]

With the monitor off use your DMM in diode mode to test the voltage across the legs of the transistor.  Google search "how to test an NPN transistor" or "test 2N3904".  Since Q1-Q9 are all the same transistor you could just compare your readings to see if Q9 is out of spec relative to the others.   To test the voltage on the vertical IC you will need to have power to the monitor.

[ed12]

i want u to chk for a leaky transistor
because if u look at the schmeatic it is first in the vertical power chain
and if leaky (not shorted) it can and will pull the 10volts u are missing
again u are looking for anything out of spec
and NOT a dead short

ed

[danielm7999]

Thanks for stickin with me on this guys, I appreciate the suggestions so far.

Ed - I checked for a leaky resistor and didnt find much. I made a short vid of everything visibly questionable that I found on the top of the board. The first thing youll see is a pin on one of the IC's (that IS an IC, right?) is a little yellowish, like it has a substance on it. But its not very noticeable and theres not much. Maybe thats not even a leak, I dunno. Didnt find anything else that looked like a leak, except some old leaks from capacitors that Ive already replaced. Q9 didnt look like it was leaking either. Heres a quick overview if it'll help matters at all:

Behmur - I googled everything you suggested and will check Q1 thru 9. Q9 didnt look like it was leaking. I'll see if its readings are any different from the others.

I havent checked pin 6 of the vert ic for +12v yet either, but will let you know which pin is pin6

[ed12]

7 pin sip chip pin 1 is outter left 6 is second to last on the right looking straight at the ic
i trust u removed q9 to e-c-b chk it for leaks (both foward and backwards
as leaks will not nessarily show up as such in curict and the rarly show up foward biased

ed

[danielm7999]

I did not take it out of circuit to inspect it...and honestly I dont know what "e-c-b" means or "checking it both forward and backwards biased".
Starting to think I have no business messing with this I'll look up how to thoroughly check a leaky transistor

[ed12]

there easy
do u have a multi meter ?
if so i can walk u through it in 1  statment

ed

[danielm7999]

Thanks for your patience with me, man...I'm fully aware that Im an idiot on some of this.

I DO have a multimeter...

AND I think I found some helpful info on the transistors. Check it out: Q1 thru Q9 are NPN as Behrmr said. I tested each of them (in circuit) and they all had readings of close to around 800 (give or take a few digits) BUT Q9 WAS READING AROUND 291 and Q4 was reading in the mid/lower 700's (about 754)

Im guessing Q10 is a completely different ballgame, cause it seems to be PNP and the reading was something like 1977/681. Im guessing that transistor is irrelevant.

[ed12]

now if u can remove q9 and re read it
foward is red on base
black to collector
black to emitor
reverse is black on base
red on collector
red on emmitor
foward should show u a didoe range drop of about .5
reverse should show u open
so in short u get 2 readings
any thing else is a leak

ed

[behrmr]

Looking at the transistor from the flat portion per the diagram

1 = E = Emitter
2 = B = Base
3 = C = Collector

[danielm7999]

You guys are awesome, thanks a lot for the info!! I'll do this tonight if I get another free minute.

[danielm7999]

Should I pull Q4 since its also fairly lower than the others?

[ed12]

let me see sec
na i think in curcit u are reading the diodes also
stick with q9 for now

ed

[danielm7999]

Ok so forward readings on Q9 out of circuit are:
Red on base/Black to collector: 781
Red on base/Black to emitter: 797

Reverse says OL open

"Forward should show a diode range drop of about .5" you said? Looks like this is more than that, right? So it's a leak and I need to buy a new Q9?

[ed12]

.5 is a range we use
.75 or so is ok
but with the probes reversed o/l is what u say ?
in what range are u with the meter ?
i olny ask because some times u need to click up a range on ohm meters
with digital we get to use a diode range

ed

[danielm7999]

I mustve been reading it wrong based on a video instruction.
Should I set it to20Kohms like in the pic? Or another setting like 200k?

[ed12]

do u c the range at the very bottm to your right ?
it looks like this  ->|- or just look up what a diode looks like
THAT is the range to use well doing these tests (leak)

ed

[danielm7999]

Ok yeah I believe thats the dial (see pic) I had it set to when I got the readings I just posted. I'll do it again though just to verify

[danielm7999]

Yep, thats the setting I had (diode) when I got 781 & 797

[ed12]

out of chassic ?
if so it is good
now move onto the verictal ic
+12 at pin 6 (put q9 back in first)
and lets see what we get
u see when we say .5/.75 it is a rounded number
.781/.797 is the believe it or not the gain of the transistor (not the hief).

ed

[danielm7999]

Yeah out of chassis. I'll put q9 back and check out the vert IC tomorrow. Will check back in then and let you know. Thanks again for all the help man! I owe ya

[danielm7999]

To measure the vertical IC pin 6 for 24 volts I should use the 200volts DC setting, right?

[ed12]

as the chip only calls for 12volt
i would use the 20 volt range

ed

[danielm7999]

Ok, just checking cause I found this video testing the k7000 vert IC pin 6 and the guy says he's looking for 24 volts: https://youtu.be/UX9IBMsg0IM?t=6m45s

Ill set for 20v range

[ed12]

well the spec for the ic its self calls for 12v
can not see why it would want 24 ?

ed

[danielm7999]

Yeah, I dunno. Just found several people saying it takes 24v to run that IC. Heres another guy: https://youtu.be/JFTkh1XXLrk?t=40s
Both guys apparently got the 24v reading and swapped out the IC and solved their problem. One guy had similar symptoms to mine. Not sure about the other.

[ed12]

ok he a 24v reading
then swaped out the ic
did he remeasure ?
its a golden question

ed