Neotec Capacitor Spec Double Check Needed.

ZPaul2Fresh8

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Got a monitor that won't power up on a cab, Neotec 27" on a SF Rush cab. All it does is constantly beep upon power up. I know the tubes are not that reliable but I don't have any glow from the neck so I need someone to double check these cap specs because the previous owner installed them and my manual I'm using says they are the wrong caps installed.

(Neckboard)
C901, C903, C904, C905: 10uF 50v; manual says 4.7uF 50v


Main Board: PCB-002B
Neck: NT-001A

I'm using this manual ftp://ttl.arcadetech.org/TTL/Test_Equipment/Monitors/Neotec/Neotech-NT-2700/NT2700.pdf

Looks like an NT2701
KenLayton said:
 
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Got a monitor that won't power up on a cab, Neotec 27" on a SF Rush cab. All it does is constantly beep upon power up. I know the tubes are not that reliable but I don't have any glow from the neck so I need someone to double check these cap specs because the previous owner installed them and my manual I'm using says they are the wrong caps installed.

(Neckboard)
C901, C903, C904, C905: 10uF 50v; manual says 4.7uF 50v


Main Board: PCB-002B
Neck: NT-001A

I'm using this manual ftp://ttl.arcadetech.org/TTL/Test_Equipment/Monitors/Neotec/Neotech-NT-2700/NT2700.pdf

Looks like an NT2701

C901/903/904/905 are all 10uF/50v, not 4.7!! Check out this pdf of the NT-2701, page 3 specifically: http://arcarc.xmission.com/PDF_Monitors/Neotec NT-2702.pdf
 
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Ok that's odd. I just looked at the pdf you linked for the very same make & model and it's saying to use 4.7uF caps... argh! Maybe buffett can chime in here!
 
I did some hunting myself. When I recapped my NT-27E, the kit I had had different values than my board did. I did some digging, and it appears Neotec changed values at some point in the production. I'm not sure if just the values changed, or some other components as well.

I had a working, but looking like crap monitor, so I preserved the values I had in my board. I didn't have the right value for one of the ones on the neck, so I actually put two caps in parallel in that position to get 20uF rather than I think 22uF. Works pretty good, though I still need to dial it on. I should be able to bench it with the TPG I just received and then fine tune it on the game PCB after.

My tube is on it's last legs. I had one gun with a current of over 10, another with about 5?, and another around 2. I was able to get one of the low ones up to 10+, but then the one at 10 dropped low, and they bounced around through multiple clean/rejuvination cycles. In the end I finally got them balanced at gun currents of 4.5. I believe some material was shorting/etc, and cleaning moved it around, but it was hard to get the guns all performing and balanced.

I have a 27" donor TV I'm going to try the tube and yoke swap into this at some point, but in the meantime have been continuing with the existing tube for the time being.

Search the forums here, a few people have documented the values from their units, and you may find that your values match someones list here. I don't have docs on what values mine were handy.
 
Ok that's odd. I just looked at the pdf you linked for the very same make & model and it's saying to use 4.7uF caps... argh! Maybe buffett can chime in here!

The IC used on the neckboard is correct on my manual, it says IC901 compared to the IC701 in your reference. I can definitely see why the previous could've easily gotten some of these wrong!
 
It just got better. I pulled the other chassis from my other SF Rush that also has a monitor power up issue and this neck board has the correct caps listed in the manual I posted.
ba0f19bbafa0ee1bf3ce6f73146d25b8.jpg


Also noticed this problem on this chassis:
5422e75b26f11d22e1713f5dae2486b0.jpg


Hopefully things are down hill from here on the 2nd chassis.

As for the first one once again, I did notice that the previous owner installed C201 backwards on the main board.
21082c0b93f0ac3ce1b2d3a3c22679ea.jpg


We'll see tomorrow if the 2nd one works now while I wait for some help on the neck caps on the 1st chassis.
 
I found this info which looks like my chassis, but the c900's are not listed :(

damn ken your everywhere.. found this site abotu a guy who fixed up some san fran rushes... they used 27" med res nt2701's, my monitor frame says atari games corp...
............................................................................................................

"K.Layton ( email deleted ken ;) ) provided some great info on the NeoTec NT-2701 monitor. This is a medium (EGA) resolution monitor. Circuit boards are marked as follows: Main board is silkscreened with "PCB-002B" on the foil side. Pincushion board is marked "F-DPC-001". Remote adjustment board is marked "NT-002" on the solder side between connectors P901 and P302. Neck board is marked with both "NT-001A" and "Li Chin" on the parts side of the board.


Re-Capacitor Information for main board:
C106 - 100 uf @ 35 volts
C110 - 1 uf @ 50 volts
C115 - 100 uf @ 160 volts
C116 - 100 uf @ 160 volts
C118 - 1000 uf @ 35 volts
C119 - 1000 uf @ 35 volts
C305 - 100 uf @ 35 volts
C424 - 10 uf @ 50 volts (upgrade this to 100 or 160 volts)
C501 - 470 uf @ 16 volts
Re-Cap on the Dynamic Pincushion Correction board:

C19 - 5.6 uf @ 50 volts Bi-Polar and High Frequency (very important!) Note: Mouser Electronics # 140-BPHR50V4.7 (4.7 mfd) or 140-BPHR50V6.8 (6.8 mfd) will work fine in this application.
Re-Cap on the neck board:

C921 - 4.7 uf @ 250 volts
C924 - 22 uf @ 250 volts (check soldering!)
So in summary, here's all the caps needed for ordering purposes since pre-made cap kits are not available for this monitor.

(1) 1 mfd 50 volts
(1) 10 mfd 100 volts
(2) 100 mfd 35 volts
(2) 100 mfd 160 volts
(2) 1000 mfd 35 volts
(1) 22 mfd 250 volts
(1) 4.7 mfd 250 volts
(1) 470 mfd 16 volts
(1) 6.8 mfd 50 volts Bi-Polar/High Frequency, Mouser #140-BPHR50V6.8.
CRT Information for the NeoTec model 2701.
It uses an RCA # A68AEG25X03 tube and matching yoke. Use B & K socket adapter CR-23 to test/rejuvenate this tube. Model 2701-S indicates a Samsung tube and matching yoke. Do NOT interchange these tubes or chassis!

Yoke Information includes Yellow & Green wires are the vertical section with 8 ohms dc resistance. Red & Blue wires are the horizontal section with 0.5 ohms dc resistance. Part numbers on the yoke are 68Q2UBZ/00 and RXE55398152. No yoke part numbers are in the manual.

Horizontal Output Information includes Transistor Q402 is the horizontal output transistor. It is a type 2SC5150 and you can use an NTE 2639 as a replacement. MCM Electronics stocks both of these at around $6 each.

Flyback Information for the NeoTec.
There's tons of numbers on the flyback (appears to be manufactured by Chun Peng). Here's the numbers I found on two of these flybacks: TLF 061A-01-12, TLF 061B-01-32, 741234BK, 3410-0180, MRCFT-249, 353024900, CP-808, 4I09, 47F10-FT-238, 47F10-FT-216, Neotec # FT-249, Happ Controls # 49-3041-00. Buying the flyback directly from Neotec is the cheapest as these are expensive flybacks.

Monitor problems encountered and solutions.
Symptom: No power up, fuse not blown. Found resistors R431 (10k, 1/4 watt) and R432 (22k, 1/2 watt) were both burnt due to electrolytic capacitor C424 being shorted. Cap c424 was originally 10uf @ 50 volts, but I suggest upgrading the voltage rating to either 100 or 160 volts. Generally if these parts are bad then the flyback is also bad too so replace the flyback also. You'll probably find pinholes in the top of the flyback as well as hairline cracks in the case around the focus adjustment pot. These flybacks seem to fail alot. Other persons have reported these components failing also and they should be checked out: C417, C419, C420, C421, C423.

Manual Errors found.
Include Resistor R431 value is wrong. It is incorrectly listed in the "Bill Of Materials List" as 1k, 1/4 watt (item #9). It should be 10k, 1/4 watt (item #19). The schematic shows it correctly. Resistor R432 value is wrong. It is incorrectly listed in the Bill Of Materials List as 100k, 1/2 watt (item #37). On the schematic it is shown as 12k, 1/2 watt which is also wrong. The correct value is 22k 1/2 watt. Always double check the resistor values installed on your particular chassis versus what's shown in the manual and schematics.

Main Board Adjustments for the NeoTec.
All are horizontal mount style with 6mm knob.

R112 - B+ Adjustment (5 k pot)
R314 - Vertical Linearity (10 k pot)
R418 - X-Ray Protection (5k pot)
R403 - Horizontal Frequency sub control (3 k pot) in series with horizontal hold pot on remote
R499 - Horizontal Position sub control (10 k pot) in series with horizontal position pot on remote
Pincushion Correction Board Adjustments for the NeoTec.
Horizontal mount style with 6mm knob.

VR3 - Phase (5 k pot)
Remote Adjustment Board Adjustments & Parts Information:
All are horizontal mount with 9mm knob.

R401 - Horizontal Hold control (5 k pot)
R325 - Resistor, 22 k 1/4 watt
R324 - Vertical Size control (50 k pot)
R323 - Resistor, 68 ?, 1/4 watt
R319 - Vertical Position control (10 k pot)
R318 - Resistor, 2.2 k 1/4 watt
R529 - Brightness control (5 k pot)
R530 - Resistor, 3.3 k 1/4 watt
R990 - Contrast control (10 k pot)
R402 - Horizontal Position control (1 k pot)
R322 - Pincushion control (500 ? pot)
R320 - Vertical Hold control (200 k pot)
VR1 - DPC Dynamic Pincushion Correction control (100 k pot)
VR2 - Horizontal Size (width) control (50 k pot)
Connectors on this board:
P401 goes to P401 on the main board. Wire color sequence is red, black, white, black, white. This connector is wired to the "Horiz Hold" and "Horiz Position" pots.
P302 goes to P302 on the main board. Wire color sequence is black, brown, red, orange, yellow, green, blue, purple, gray, white. This connector is wired to the "Vert Size", "Pincushion", "Vert Position", "Vert Hold", and "Brightness" pots.
P101 goes to VR1 and VR2 connectors on the pincushion board. Wire color sequence is orange, red, brown, black. This connector is wired to the "DPC" and "Horiz Size" pots.
P901 goes to P903 on the neck board. Wire color sequence is brown, red, orange. This connector is wired to the "Contrast" pot.
NOTE: If "F-DPC-001" Dynamic Pincushion Correction board is installed to the side of the main board, these changes should be noted on the remote adjustment board:
R322 - Pincushion pot is not installed.
R323 - Resistor is not installed.
R318 - Resistor is replaced with a wire jumper.
Neckboard Adjustments:
All are vertical mount style with center terminal facing rear and 6mm knob.

R950 - Red Gain (2 k pot)
R951 - Green Gain (2 k pot)
R952 - Blue Gain (2 k pot)
R936 - Blue Cutoff (500 ? pot)
R937 - Green Cutoff (500 ? pot)
R938 - Red Cutoff (500 ? pot)
Manufacturer Contact Information:

Neotec Graphic International, Inc.
2721 N. Towne Avenue
Pomona, Calif. 91767
Phone: (909) 626-9889
Fax: (909) 626-0990
www.neotecgraphic.com

I just need to know the actual values on those Caps in my OP. I have 2 of these chassis' but the previous owner changed about every ES Cap on both chassis' in attempt to fix the monitors and he definitely made a few mistakes.
 
5059c69a2064e7eadde848d66db32307.jpg


Is this transistor @ q402 the HOT? Whatever it is, I believe it is bad. It is shorted on all pins. The other chassis I have tested ok with it having continuity from B to E and about 1K from the middle pin to B or E.

Insights please. Thank you.
 
I believe Q402 is the HOT and it being bad would definitely explain your monitor power supply being in shutdown (the chirping sound means that the power supply is detecting an over-current (short) and is shutting down).
Double check the flyback too as a bad flyback can take out the HOT (check for cracks and/or oozing goo).
 
I'll check it a bit more closer. I don't see any cracks or any other signs of damage. I did measure a few of the common caps that cause the HOT to go and I got 3 of them that have continuity, probably bad caps, no?
 
I'll check it a bit more closer. I don't see any cracks or any other signs of damage. I did measure a few of the common caps that cause the HOT to go and I got 3 of them that have continuity, probably bad caps, no?

If you are reading "continuity" across a cap that is out of circuit, then I'd say its definitely bad.. not even a capacitor any more! If you are reading it in-circuit then all bets are off as the rest of the circuit will impact the measurement. (btw... using an ohmeter to measure a capacitor is not really going to work so well... you need an esr meter for that).

Also... the original cap question (4.7uF v 10uF on the neck board)... probably not going to make much difference, certainly not going to kill the supply. Maybe if one of the caps shorted it could but then the cap would likely blow up anyway.
 
If you are reading "continuity" across a cap that is out of circuit, then I'd say its definitely bad.. not even a capacitor any more! If you are reading it in-circuit then all bets are off as the rest of the circuit will impact the measurement. (btw... using an ohmeter to measure a capacitor is not really going to work so well... you need an esr meter for that).

Also... the original cap question (4.7uF v 10uF on the neck board)... probably not going to make much difference, certainly not going to kill the supply. Maybe if one of the caps shorted it could but then the cap would likely blow up anyway.
I figured that much about the cap readings so I compared them to my other board which measured good.

bfed8a1a8c8158a018bc2c2fac2c45af.jpg
 
I'm back 10 months later...

Figured I'd get back to this monitor project. So I found I only have 65 volts @ R112 (HOT B+ Pot) so I start tracing back and measuring and my 120v drops after the component D101...

It's a 4-pin diode and from left to right (looking at the bottom of the board) I'm getting these voltages.

1. 120v
2. 65v
3. 0v
4. 65v

Is anyone able to confirm these voltages, or have a test I can perform with the component out-of-circuit?

Thanks!
 
Chirping on the Neotec almost always mean bad HOT. You can check it in circuit. The HOT dies very easy on this chassis for some reason, one of the backwards caps may have taken it out.
 
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