WG6100 - Spot Killer on

dogbowl

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I've got a Tempest that had been working properly. Turning it on recently, F100 immediately blew. The spot killer is now stuck on.

It has a LV2000 installed and I believe that to be working correctly. The 2 leds on that board light up and I read +/- 26 on P100 - Pins 3 and 6 respectively. I've tested all of the chassis mounted transistors for continuity, and those seem to be all okay. I don't see any cold solder joints with my connectors either..

From a Bob Roberts kit, I've replaced C100, C101, D100, D101, D102, D103, R701, and R106 (That last one was burnt and tested bad after removing).

Two issues I know I have:

On the 2N3716 at Q605 I read +25.97. However on the 2N3792 at Q606 I read +10.27 (?!?)
My B+ reads only 24.33.

Thoughts? Next steps?
 
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Still blowing the fuse after replacing all that? check the 4 transistors in the back of the deflection board with the heat sinks...
 
No, the fuses are steady now. I also don't hear any "chatter" from the monitor. Would that be because my B+ is too low or because the spot killer is on?

Can those transistors be tested in circuit?
 
Where are you reading the B+? Best place is where the orange wire from the HV cage connector goes to the neckboard.

Have you checked/rebuilt the HV cage? Check ZD902 (not to be confused with D902)...
 
I'm reading B+ on the back of the neckboard (behind where the orange wire connects)

I have not done any updates to the HV board or the neckboard (although I do have the parts from a Bob Roberts kit). Could a bad HV board cause the spot killer to turn on?

Should I discharge the monitor before remove the HV board to work on it? And if so, is there anything different about discharging vector monitors than a regular CRT?
 
Not for the 6100. If you had a G05 with an HV diode in your anode wire, then you'd need to discharge it differently.

Spot Killer comes on whenever there is a problem displaying the picture completely in both directions. This can be caused by no signal detected from the board (due to a faulty pcb or bad wiring/connectors) or a problem with the monitor - in your case a low B+ voltage.

A problem with the HV board can definitely cause the B+ to be way low. When putting the parts in, make sure to replace the HV adjustment pot, too...
 
Went through the parts on Bob Roberts standard and additional 6100 kit tonight(Feel like I've damn near replaced everything on these boards).

The spot killer is still on. I tested the X and V voltages on the PCB and those were both within range. I can now read a high value of 50V on the B+. Also, I tested for DC on the 4 fuses on the deflection board and read 0V. (Maybe thats why I'm not blowing fuses any longer???)

What would be the best way to test the AC power coming to the monitor. If I read the schematics correctly, J23 is bringing +50 AC in. Is one of the 3 wires on that connector a ground?


(On a side note - I found some definite signs of past repair work and some odd components on the HV board. C905 was a 33uf 63V and C901/902 were 220uf 220V.)

Thanks for you help so far modesst
 
Yes, it does change values. Goes from a low of 22ish up to 50V.

FYI, I am still reading +/- 26 on Pins 3 and 6 coming off of my LV2000, so I believe that to be working properly still...
 
(On a side note - I found some definite signs of past repair work and some odd components on the HV board. C905 was a 33uf 63V and C901/902 were 220uf 220V.)

C905 value was changed in different manual revisions. Referred to as 63V, 150V, 160V.

C901/2 should be 100uf minimum 35V
 
Some more detective work. Following Marvins guide, I tested Pins 1 and 8 on P900 on the HV board Pin 1 read 25V but pin 8 reads 0v. So from that, I then checked the chassis mounted transistors again.

No shorts, but I do get some odd readings. When I read from ground to the outside of the transistor (the collector?) I read 12V on both Q606 and Q706. I get the expected 25V on Q605 and Q705.

Is that a sign those chassis transistors are bad? If I follow the flow chart from the monitor guide, it also points me to them.

Whats the best way to test them? Could testing for a short on them not be enough?
 
Did you miss my previous post? You have two wrong caps.
C901 100uf
C902 100uf
Both with a minimum of 35V - personally I'd use a 50v or 100v instead.
 
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Those values for the C901/902 were for the previously installed parts. I replaced them with caps from a Bob Roberts 6100 kit.

Made some progress last night. It turns out that the Q103 transistor was bad. Wasn't shorted to the chassis, but once I pulled it it tested bad.

Replaced that and that brought my B+ back to 180, spot killer turned off and the monitor came back to life. Progress!

But now on to the next problem. I'm missing the bottom half of the screen. I know my chassis transistors are all good so I guess I need to focus on the Y amplifier/ deflection board. Nothing looks burned and I've replaced most parts; guess I'll start with Q600/ Q603 and Q604.
 
Hi,
I have been looking around at Tempest repairs and came across your repair efforts. Can you tell me the things that you did not get yours up and running? I keep reading about nicknames for things like spot killer. Is this just an led on the deflection board? Are the two leds on the main and aux game board suppose to be on?
 
You have cold solder joints. You need to reflow. The bottle cap transistors on the frame the blue white purple and green red yellow wires where they meet the sockets for the transistors also reflow the header pins on the deflection boards where the red holders plug into.

Andrew

Those values for the C901/902 were for the previously installed parts. I replaced them with caps from a Bob Roberts 6100 kit.

Made some progress last night. It turns out that the Q103 transistor was bad. Wasn't shorted to the chassis, but once I pulled it it tested bad.

Replaced that and that brought my B+ back to 180, spot killer turned off and the monitor came back to life. Progress!

But now on to the next problem. I'm missing the bottom half of the screen. I know my chassis transistors are all good so I guess I need to focus on the Y amplifier/ deflection board. Nothing looks burned and I've replaced most parts; guess I'll start with Q600/ Q603 and Q604.
 
The leds from the main and aux boards should be on. The led on the deflection board from the monitor should not be on if it is it indicates a problem with the monitor or the board.

Andrew

Hi,
I have been looking around at Tempest repairs and came across your repair efforts. Can you tell me the things that you did not get yours up and running? I keep reading about nicknames for things like spot killer. Is this just an led on the deflection board? Are the two leds on the main and aux game board suppose to be on?
 
Is there a way to test the game board to rule it out? I see that some people are able to pull up the attract screen on an oscilloscope. How would one do that safely?
 
Take your scope leads connect channel 1 to X and channel 2 to Y ( test points on the Tempest main board). Set your Volts per division to 2V or so and put the scope in X-Y mode. I usually totally unhook the monitor when I do this.

Im guessing the issue is either the cold solder joints, or a bad 2n3716/2n3792. I doubt this is a board issue.

Andrew
 
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