Sanwa PM 1745 Chassis, Need Help.

72Demon

Active member
Joined
Dec 2, 2008
Messages
442
Reaction score
82
Location
Kaneohe, Hawaii
I think I messed up my Sanwa PM1745 Chassis. It was giving off colors so I pulled it out and reflowed solder to the area that would correct if you pushed on it.

The problem is when I finnally had time, and hooked it back up much later, I connected the "CRT/E" wire to the "P1 N" pin on the chassis by mistake. When it powered on you could hear a loud clicking sound thru the speakers. I quickly powered it off to see what happened. After inspecting it, I found out what I did wrong, and found both fuses blown, 1.6A 250V and the 4A 250V. I replaced both fuses and connected the CRT/E wire correctly to the neck board not the chassis. Now it only blows the 1.6A 250V fuse. There is no neck glow. Upon further inspection, I believe the HOT is bad. I have not been able to find the diagram for this monitor and I am not sure what else could of been damaged by my mistake. There is no obvious visual damage. So far I think I need a C5143 HOT, which I have not been able to locate. This chassis is totally different then any others I have worked on. My research shows it is compatible with Sanwa 27z21c, Rodotron 666a-29, Wei-ya C31291a. Although I am not positive since some of those are for 29" monitors. This is out of a Namco Classic NFL Football with 27" monitor.

Does anyone know what else may of been damaged or what else I should check?
Does anyone know where I can get the HOT or other parts that may be needed?
Does anyone have the schematics for this chassis?

Thank you for reading my post.
 
Here's the PM1745 schematic. I know I already e-mailed you this but thought I'd post it in case someone else needs it in the future.
 

Attachments

  • PM1745_schem.pdf
    87.4 KB · Views: 658
  • PM1745_diag.pdf
    26.2 KB · Views: 430
Can anyone give me the voltage pinouts for this thing? I accidentally got one thinking it was an MS8. It doesn't have that same connector that MS8/MS9 uses, so I will need to rig something up.
 
I know mine is working, so I don't think I will get rid of it. Unless I find out it's not compatible with astro city/new astro city toshiba tubes.

I would trade it for a working Nanao MS8 or MS9 though. Or maybe for a few non-working MS9.
 
Did you order the HOT?
Do you have B+ to the HOT?
If not Is R442 Open?

Thanks for chimming in Ohmerrone. I did get another parts PM1745 chassis. This one seems to have the same burnt resistors and HV shutdown as the other Sanwa PM1745 Thread. The thread that you recommended:

Replace R819 3.9 ohm and
R806 69. ohm
R808 10k ohm check the ohms out of circuit
may be good just looks bad.
When any traces are lifted i would suspect all the parts in power supply
if you just replace the resistors it will not complete the repair to PS
Check or change these parts.
D803,D804
Q801,Q804 Q805,Q802,Q803 Q806 for shorted or leaky.
C811 and repair grounds.

Now do you think I am better off rebuilding my original one, need to take the HOT, D404 & Q404, they are both showing shorted. Not sure what else. The R442 is not open.

Just worried about the spare one in HV shutdown if that is a common problem with the PM1745, if I replace all the bad resistors and it happens again, like the OP in the other thread. I am providing a picture of the spare chassis showing the same problem area as in the other thread. Burnt area is center top of pic.
 

Attachments

  • Sanwa PM1745 HV Shutdown.jpg
    Sanwa PM1745 HV Shutdown.jpg
    105 KB · Views: 141
Can anyone give me the voltage pinouts for this thing? I accidentally got one thinking it was an MS8. It doesn't have that same connector that MS8/MS9 uses, so I will need to rig something up.

Not sure if this is what you need:

Looking at end of connector starting at top left:

First Row:
Yellow w/ Green strip=Field Ground
Black=AC 110V
Blue=DEM
smaller gauge Blue=Blue signal

Second Row:
White=AC 110V
smaller gauge Black=Ground signal
smaller gauge Green=Green signal

Third Row:
Blue=Dem
smaller gauge White=Sync signal
smaller gauge Brown=Red signal

I hope that is clearer than the pictures I took.

Also, sad to say I do not have any MS8/MS9 to trade.
 

Attachments

  • Sanwa Connector.jpg
    Sanwa Connector.jpg
    100.3 KB · Views: 133
  • Sanwa Connector Pinout.jpg
    Sanwa Connector Pinout.jpg
    77 KB · Views: 116
Need all New Parts in regulator!

If its so common then looks like you need to get up to par
or you'll never fix one.
I don't find it common otherwise i would have seen all these chassis
need these parts..maybe changing the caps before its to late might help.
When the regulator fails then many more parts are likely to fail.
or man made problems like hooking parts up wrong.
anytime the output stage is shorted it will burn up the regulator circuit..
Get your parts together make the regulator work first,then apply
it to the Horiz-output circuit,of coarse replace the output parts as well.
Its very hard to read the schematic,may have to print it out and match up the
locations and part.Don't test parts in circuit.don't be lazy.or send it out for repair!
 
If its so common then looks like you need to get up to par
or you'll never fix one.
I don't find it common otherwise i would have seen all these chassis
need these parts..maybe changing the caps before its to late might help.
When the regulator fails then many more parts are likely to fail.
or man made problems like hooking parts up wrong.
anytime the output stage is shorted it will burn up the regulator circuit..
Get your parts together make the regulator work first,then apply
it to the Horiz-output circuit,of coarse replace the output parts as well.
Its very hard to read the schematic,may have to print it out and match up the
locations and part.Don't test parts in circuit.don't be lazy.or send it out for repair!

I am definitely not up to par, that is why I appreciate forums so much for their helpful members. I am not sure if it is a common problem with the PM1745, that is why I asked which chassis I should repair. I have printed out the schematics, but still having difficulty reading it. Do you offer repair services for the PM1745?
 
Not sure if this is what you need:
Hrm, it looks like my chassis has a different set of connectors than yours. Yours looks like a regular molex or something similar, mine has 2 connectors. One has RGB S G and the other is for power. It looks like it takes AC and DC? I was really looking for the power pinout for the connectors on the chassis board.

I will take a picture of the connector I'm talking about later today. If memory serves the two things connected on CN801 and CN808.
 
I am definitely not up to par, that is why I appreciate forums so much for their helpful members. I am not sure if it is a common problem with the PM1745, that is why I asked which chassis I should repair. I have printed out the schematics, but still having difficulty reading it. Do you offer repair services for the PM1745?

The print is bad that's why you compare it to the parts and location with
good notes for numbers on the part,the schematic lines and symbols are easy to read.
the best thing about the older chassi you can see the pcb path and follow it with
your ohm meter..
all parts are used in many types of raster scan
like q8?? and other transistors in the regulator circuit,i don't use NTE or ecg in general
sometimes i have to.the correct resistor wattage is important not a 2watt in place of a .5watt
a good looking circuit repair is a good thing..repairing open pcb use insulated thinner wires
not a solder bead to run the path or solder wick-it,i know it works but come on...
it may open again.. with a wire its good to go.

I always say if this is your first and last repair send it out for repair,,you are not prepared
to fix this i don't care if you know how! pull the monitor set it up,so its comfortable to TS
Good lighting is a plus in component level repairs
I don't service for outside customers,just company's
one because i'm not prepare at home to.When a circuit has a whole lot of bad parts
it maybe best to send out for repair you will get a warranty with it too.

Dlp.Plasma,Lcd,RPTV Led etc,board i will do in the home,component level repairs i do in shop.
I would have done a cap kit before replacing any
semiconductors that way i know my caps are good then i can work from there.
 
Does anyone know the lone resistor value which is located on the solder side of the chassis? Both of my Sanwa PM1745 have it blown. Can not read the color code and the values are unstable. Not sure if it was added as a later mod or if it came from the factory that way.

Its hard to see in the pic, but it is in the top center, that is the one I need the value for.
Thanks.
 

Attachments

  • Sanwa PM1745 HV Shutdown.jpg
    Sanwa PM1745 HV Shutdown.jpg
    105 KB · Views: 43
Does anyone know the lone resistor value which is located on the solder side of the chassis? Both of my Sanwa PM1745 have it blown. Can not read the color code and the values are unstable. Not sure if it was added as a later mod or if it came from the factory that way.

Its hard to see in the pic, but it is in the top center, that is the one I need the value for.
Thanks.

I don't know of any mod's to the regulator circuit.
there are case's where the company decides to revise
or update a circuit..more often when a transistor is obsolete
and is changed to a newer type trans.
I find if the circuit gets fix with the normal parts and last
for many moons than it doesn't need a revision!
i have fixed this circuit before,and i used what was there.
the bad resistors are a derived of the over current from the transistors
and shorted or leaky diodes and or bad caps,over voltage can damage
the small caps often shorting them.
When the pcb is open, replace all the component's in that circuit.
then if you want to see if im right.. that you should replace all the components
you can put back a few to see if i was wrong about replacing all the parts..

I do have the {service manual} but this site only allows
certain file size to be uploaded..i forgot i had the service manual..
if you pm me your e-mail or post a website i can upload it.
and i can post it for anyone to take.
its has a pictroial and parts list and crapy schematic and description of circuits..
Of the sanwa model 27Z21C or whats silk screened on the pcb pm1745c
 
Thank you for sending the service manual, the parts list too will be very helpful.
No problem.
Ok there is a resistor on the bottom of pcb a 10000 ohms .25 watt
flameproof the circuit board company left out the thru holes and {r}
location..it runs from r810 to base of q804 or keep it in and let it be the
last part replaced, so you don't loose the connection points if you like..
its on the schematic have to match it up the the parts list.
its very easy to lift the trace while removing parts.Good Luck!
 
Last edited:
Thank you, that is exactly the resistor I was asking about. I had already removed it and taken it in to a local electronic supply store hoping they could figure out what it was, but had no luck. That resistor is fried on both of my Sanwa PM1745 chassis.
 
Fixed Yet?

Thank you, that is exactly the resistor I was asking about. I had already removed it and taken it in to a local electronic supply store hoping they could figure out what it was, but had no luck. That resistor is fried on both of my Sanwa PM1745 chassis.

Heres a picture where the resistor goes.and
and pictures on a way to test the powersupply.
with the Horz-drive circuits and without..
by opening the dc fuse and adding it back in.
the jumper green wire is the Hot ground.
Good Luck!
 

Attachments

  • IMG_20120509_093154.jpg
    IMG_20120509_093154.jpg
    85.5 KB · Views: 97
  • IMG_20120509_092351.jpg
    IMG_20120509_092351.jpg
    90.6 KB · Views: 99
  • IMG_20120509_092343.jpg
    IMG_20120509_092343.jpg
    88.7 KB · Views: 98
  • IMG_20120507_165327.jpg
    IMG_20120507_165327.jpg
    85.1 KB · Views: 96
Thanks Ohmerone. I sent you a PM. But as a recap here is what I changed on the chassis that has the good HOT and no blown main fuses:
C811
R808
R806
R808
R810
R817
R819
D803
Q801
Q802
Q805
10K ohm 1/4 watt resistor on bottom of chassis.

Result: no neck glow and R817 fried. I am thinking about swapping over to my original chassis. Any suggestions?
 
Back
Top Bottom