Re: 32" Armstrad psu 05ta071b
Hallo,
I have checked the items from your list (including replacing and changing work) and discovered no abnormalities. At least up to the test of the two Zener diodes.
There are wrong values . D318 provides 0 volts and D315 I had first measured 10.8 volts. After replacing it was 11.6 volts. Since I have no Z 2.4 here, I'm considering to switch 4 1N4148 in series possibly. I could , if necessary, adjust the 2,4 volts with a trimmer. This would be only for testing. Should it actually be due to D318 , I'll order a new diode....
teslacap
Member
Last Activity: 08-27-2013, 11:27 PM
Joined: 06-06-2012
Location: North
-
Last edited by teslacap; 08-27-2013, 11:26 PM. -
Re: 32" Armstrad psu 05ta071b
Good morning,
my statement in the beginning wasn't exactly in all items. I found out now that of course the led is red for a few seconds after switching on mainswitch and expires after to stay about a weak glimmer. Quite interesting is the fact that I can see a large sinewave on the oszi, when I put an inducting coil near the transformer on the secondary psu-part. It seems that the switching part is working in basic function. Could be that there is something wrong with the dc- way after this section. Without schematics it's hard...Last edited by teslacap; 08-26-2013, 11:34 PM.Leave a comment:
-
Re: 32" Armstrad psu 05ta071b
Hi,
I have checked the polarity, it is correct and I use capacitors from KMG.Leave a comment:
-
32" Armstrad psu 05ta071b
Hi there,
recently I became an Armstrad LCT3285 in, with only Power LED on, but else no function at all. On the PSU I saw a bulg 1000uF/25 capacitor and replaced it and also the whole capacitor-set in the neighbourhood. After I got the result, that even the power led was off now and nothing else changed.
That's quite motivating! I'm no beginner and repaired many psu's before, but I've no idea what to do now even because it's hard to find a schematics of this psu inside the internet. Can anybody help me, who has experience with this unit?
-
Samsung Syncmaster: Spareparts wanted or given
Hi there,
have lying around here 3 Samsung LCD-Monitors, where in each case probably only the VGA-board is defective. Does anyone have such boards left? Or does someone need anything other than the VGA-board? Please contact me in this case privately. The models are: Samsung Syncmaster 720N, 901B and 913V
Cheers -
Re: FS Scaleoview T17-2: inverter pumps for two times before silence
that was quite be done, I'm no beginner..
I think the secondary wires are not connected directly to this outgoing-pins
such hybrid smd-circuit might be a little different.Leave a comment:
-
Re: FS Scaleoview T17-2: inverter pumps for two times before silence
is self-evident, that the ohm measurement only took place while the monitor was turned off. So, my ohm meter is not blown.Leave a comment:
-
Re: FS Scaleoview T17-2: inverter pumps for two times before silence
Hi jetadm123,
when the monitor is switched on, the PS-voltage decreases from 19 to 17 V,
during the inverter tries to start. Between those 3 pins of transformer-secondary I measure nothing (even in M-Ohm range), might be some
circuit inside which perhaps interrupt direct galvanic connection or
both transformers are secondary open burned? The CFL short lights up!
In this case there must be a flash between the open wires? Hard to imagine..
Without schematic...Leave a comment:
-
FS Scaleoview T17-2: inverter pumps for two times before silence
Hallo,
after I got this monitor, I found that the inverter is pumping. High voltage tries switch on for two times an then silence. The switching MOSFETs FDS6612 and FDS4435 seemed okay when tested in preliminary examination procedure (no drain-source short on ohm-measure). I replaced the two big 220uF caps without any better result. Does anyone have this monitor repaired before?
Cheers... -
Re: "poor Screen" on a Xerox 700P
Hallo retiredcaps,
thank you for your "tough-tip". Actually the item 2 was the bug-killer.
I repluged everything on the mainboard and also put the MCU out of the socket for to polish the contacts. After back plugging I got full colors! Great!
Cheers...Leave a comment:
-
Re: "poor Screen" on a Xerox 700P
Hi jetadm123,
yes of course I did. That was one of my first thoughts. But the resolution during this two pics were made was 1280x1024 with 32-bit colours. That is definitely not the errors cause.
CheersLeave a comment:
-
"poor Screen" on a Xerox 700P
Hallo,
after connecting a Xerox 700P to the computer, I got a very poor screen-picture. That seems similar to 8-bit resolution, but is for sure something else. Is that symptom known by someone? I put 2 pics into the attachment.
Cheers... -
Re: Siemens-Nixdorf MCM 2105 NTD vertical deflection collapses
Hi ben7,
it seems that I got the wrong schematic, because haven't found an IC 701 inside this monitor. Also some transistors which are inside aren't found on the schematic. That might be for sure a different chassis. I will reply if I have found the right schematic.Leave a comment:
-
Siemens-Nixdorf MCM 2105 NTD vertical deflection collapses
Hallo,
is anybody experienced with the Siemens-Nixdorf huge crt-monitors? Here the vertical deflection collapses until there is only a horizontal white line visible. Sometimes the screen appears, for 1-2s, then collapsing again. I got a schematic from the MCM 21T1 Series, where is an IC702 responsible for the vertical deflection. Until now I did not open the chassis, just ready for experiences of somebody here. Thank you! -
Re: Samsung 901B S finds no input signal
Hallo,
after switching on I got a voltage over the 0,00V Cap from about
4,92V during for the same time this window-frame appears, where
analog oder digital input is toggling. After around 20s the signal
breaks down to 0,00V. I think I will need a second-hand video board.
CheersLeave a comment:
-
Re: Samsung 901B S finds no input signal
Good evening @all,
@selldoor: this brown spot was only color. I cleaned it away with a little alkohol
(of course not inside me, but onto the platine-surface)
@jetadmin, momaka, budm: I will go on with the monitor when I have enough time left to do. In the moment I'm tired, because a lot of other important things needed to be done today. Thanks for your inspiring tips. I will check asap.Leave a comment:
-
Re: Samsung 901B S finds no input signal
Hallo momaka,
thank you for your reply. I checked the pins from SUB-D and resoldered
it. After I checked the voltage over each visible capacitor (have no schematic)
and wrote the values on it (see picture). Also I tried the pin5/pin6 method
(bridged with 50 Ohms) on the Novatek IC. Surprising was the changing of sceen
message after. Instead of toggeling between analog and digital there appears
"you use the wrong resolution, try 1280x1024 60Hz". That's quite telling.
I'm not quite...Last edited by teslacap; 06-09-2012, 08:53 AM.Leave a comment:
-
Re: Gericom S1902D - flashing Power LED
Hi jetadm123 and budm, thank you for those hints.
The 2SC4672 provides a transit-frequency from about typical 210 MHz.
This is a walk-over for the 2SC5705, because its transit frequency is much higher, around (290) 330MHz.
I've heard a similar little "coil-noise" even in original-running ciruits.
But the level is such minimal, you won't regonize it, near sitting by.
This monitor is already closed now. I will test for one day before shipping.
And the customer will...Leave a comment:
-
Re: Gericom S1902D - flashing Power LED
Hi budm, I already have changed the two tuning caps (150nF) against new one. Thanks..Leave a comment:
-
Samsung 901B S finds no input signal
Hallo there,
after repairing the inverter-board of a Samsung 901B S, there is still a problem
with the input signal. Even though a signal is connected to the VGA-SUB15, the monitor toggles between digital and analog input (screen-window) and doesn't process the signal onto the screen. Therefore I guess something on the VGA board is damaged too. Does anybody know this bug?
No activity results to display
Leave a comment: