g07 vertical collapse

tron guy

Super Moderator
Staff member

Donor 12 years: 2011, 2015-2025
Joined
Jun 26, 2007
Messages
23,144
Reaction score
2,591
Location
Eureka, California
Mod has been a great help via pm on a couple of chassis I've had issues with, I just want to get this out there for some feedback and possibly where to source parts (today).

Anyway, I had 2 perfectly working, rebuilt (complete bob kit) g07's. They weren't wide enough for me so I decided to get the bob roberts width cap kit.

Additionally I read where mod had changed the diode and resistor at D507 and R525 for additional improvements in the width of the picture. (horizontal mode)

Long story short I put my new D507 diode in position D504, causing smoke on 2 chassis.
Replaced the parts (d507,d507 and R525) again, on the first chassis that I let run for like 40 seconds, fixed it perfect.

2nd chassis, which I had on for maybe 3 seconds, because of what happened to the first one so I was being cautious,is in vertical collapse. Changed (d504, D507 and R525) on these as well, still vertical collapse.

Everything tests good, in the entire 400 section. I did not pull the transistors at 401 and 402 but I tested them with my simpson analog meter in circuit, same exact readings as the working chassis.

I'm thinking of going and buying another FR401 (I think that's the position) and the two transistors, I have a new set of pots I could change out as well.
Does frys or radio shack have the equivalents I need for FR401 X401, and X402?

or any ideas would be great
 
Ok so if I did what I think you are asking.... I checked for continuity coming from each leg of 401 and 402 in each direction where the trace led. It's there, no problems.

So I'm using my simpson analog meter and checking/testing D504, D507, R525

In Rx1 mode:
good chassis:
D504=11.5 ohms
D507= 11.5 ohms
R525= 11.5 ohms
bad chassis:
D504= 10.9 ohms replaced with 1n4148 from bob roberts (diode is good)
D507= 13.75 ohms replaced with equivalent from bob roberts (good)
R525= 13.75 ohms

so I go to Rx100
Good chassis:
D504=3.5 ohms
D507= less than 1 ohm
R525= less than 1 ohm
Bad chassis:
D504= 5.5 ohms
D507= 7.5 ohms
R525= 105 ohms
 
You can't acurately check diodes with a analog Simpson. You need to use a DMM with diode function.

ok in that case I have tested them all out of circuit, and they were fine.
I wasn't sure which way was better, thanks for that.

back to the drawing board.
 
ok when I was pulling them out, one of the legs broke off. NOw it is possible that one of them was already broken (I hope).

Since I have them out I may as well replace them both. Does radio shack or frys have equivalents to replace x401 and x402?
 
ok when I was pulling them out, one of the legs broke off. NOw it is possible that one of them was already broken (I hope).

Since I have them out I may as well replace them both. Does radio shack or frys have equivalents to replace x401 and x402?
You can always put the good one in the other side and see if your problem follows.....
I doubt Radio Shack sells shit, last time I went there the kid didn't even know what a heat sink was.
Bob Roberts sells the replacement transistor...
 
You can always put the good one in the other side and see if your problem follows.....
I doubt Radio Shack sells shit, last time I went there the kid didn't even know what a heat sink was.
Bob Roberts sells the replacement transistor...

Is one of them (x401 or x402) more likely to be the culprit? I was going to swap them (dokerts suggestion earlier in this thread) to see if anything changed. Now that I have one only intact transistor, I suppose I could move it to the other position and leave one blank, but will that give me any relevant information?

thanks for the input.

Looks like frys is my only local option then (if it is even an option, anyone know the value or part # I should be looking for from them?)
 
replaced both with new NTE375's no change, vertical collapse still.

Now I didn't use any joint compound. It came with the little plastic protectors. Generally I use both, lol. But when I tested both the good and bad chassis, the transistor was shorted to the heat sink on both, so I figured it didn't matter.


I've got a replacement pot kit, should I change them, is it relevant?
 
pictures

wow this whole picture bullshit with klov is starting to piss me off.
I'll go re-shoot some others and be back
 

Attachments

  • 019.jpg
    019.jpg
    92.1 KB · Views: 44
  • 020.jpg
    020.jpg
    103.9 KB · Views: 42
  • 023.jpg
    023.jpg
    101.1 KB · Views: 42
  • 024.jpg
    024.jpg
    102.2 KB · Views: 38
try again with a few others
 

Attachments

  • 028.jpg
    028.jpg
    91.3 KB · Views: 29
  • 029.jpg
    029.jpg
    97.8 KB · Views: 39
  • 030.jpg
    030.jpg
    101.5 KB · Views: 75
  • 031.jpg
    031.jpg
    106.1 KB · Views: 60
well after looking at these pictures I went through with a magnifying glass and a flashlight to see if there were any solder bridges, etc. Didn't see any. But I did pull out some cotton swabs and alcohol and spent about 20 minutes cleaning up this bottom side of the chassis.
 
well after looking at these pictures I went through with a magnifying glass and a flashlight to see if there were any solder bridges, etc. Didn't see any. But I did pull out some cotton swabs and alcohol and spent about 20 minutes cleaning up this bottom side of the chassis.

But yet you still missed the several cracked traces that are evident in the next to last pic you posted.
 
But yet you still missed the several cracked traces that are evident in the next to last pic you posted.

Well I obviously haven't acquired the eye for it, or I would have recognized that. Can you be specific as to the locations (maybe the #'s?) then I can go test them all and repair them all. Obviously if there are a bunch I don't expect you to name them all, but a couple ought to get me going.

thanks for the effort on this one Dok
 
Test that whole area for continuity. Specifically, look around W424, R405, C403, Pin 15 of IC501, R403, just to name a few.

Also break out your spare toothbrush and 90% or better isopropyl alcohol and scrub the shit out of that nasty bitch.

Remember, if it looks like a scratch it may actually be a crack.
 
Back
Top Bottom