• Please review our updated Terms and Rules here

Vectrex Repair (another no buzz 3GE version)

4 days ago i have only changed both 2n3905 , integrator caps and socket of both 34001, but the problem not resolved...at this point i have to replace socket of other remain chips, or i reball solder points of it....

It's the finger issue a very mystic problem. i have tested both 34001 with new, but not resolve.

If i put totally finger on top of 34001 all vectors going out to top right corner of screen and when i remove finger it return slowely in correct position!

Question, the little compensator capacitors 10nF (104) from power line 5v and gnd instslled to all chips, can it cause this type of problem (finger problem)?
 
I have readed again discussion and before find the 7905 faulting i have socketed 4066, 34004 and 4052 on post 27, then i jave replaced 7905 and noted the problem of distortion at cold, and in post 59 i have the same square vector out of correct position.....at this point the problem is probably bottom of 4066, 34004 or 4052....
 
Last edited:
And today at cold.........bahhhh
 

Attachments

  • Screenshot_20231209-111705_Telegram.jpg
    Screenshot_20231209-111705_Telegram.jpg
    622.2 KB · Views: 7
Yes dave, now i jave used phon to hot this zone and all going to perfect working, then i have sprayed wirh cold air in same zone and again going complete distorted, the problem is here....i think so the sockets, originally not present for all four chips, generate a capacitance or is another issue in this zone, or 104 caps or zener diode or resistor, now i remove all socket and test all other component one to one at cold and hot ....
 

Attachments

  • 20231209_125645.jpg
    20231209_125645.jpg
    970.2 KB · Views: 10
Last edited:
Please do NOT remove the sockets (if you haven't already). Adding a socket should NOT make any difference to the performance - unless you messed up the original desoldering and soldering.

Better to use hairdryer and freezer spray to isolate the problem to one component and then to fully check the connections one at a time with a multimeter.

If evidence of a solder issue, then is the time to warm up the soldering iron - but only then.

Dave
 
Some of the soldering (for example, on the left lead of C307 in your photograph) could be neater.

Please post some close up photographs of the top and bottom of the PCB (around this area) in good light and focused so I can make some suggestions about tidying up the solder joints etc.

Dave
 
Hi Dave,
too late, I disassembled everything, desoldered everything, removed the sockets and reassembled everything without the socket, and I found the socket in the photo of the 34004 with pin3 (GND) bent as you can see! Once everything was reassembled I turned it on and it was perfect, still that square of the DEFLECTION PROTECT screen with the left part moved but much less, and shortly after turning it on it was almost OK, I redid the DAC OFFSET adjustments (without an oscilloscope only a multimeter because 'I didn't have it nearby) and after less than 2 minutes it was already ok. I was there and I also cleaned the area that you told me was dirty, it was fluxing, and I changed the 1n4148 diode on the Z axis output. I left only the 4066 and the 1808P8 socketed which was already socketed before I opened it for first time. Now let's see what happens tomorrow. It seems very strange to me but this is what I found. The whole story will follow eventually!
 

Attachments

  • Screenshot_20231209-195147_Telegram.jpg
    Screenshot_20231209-195147_Telegram.jpg
    341.3 KB · Views: 10
Ah, pin 3 is a non-inverting input to one of the OPAMPS. If it was just resting on a solder pad (and wasn't soldered) that would account for all of your problems.

Didn't you notice when you soldered the pins of that IC socket that one of the pins was not poking through the PCB?

Yes, flux and dirt needs to be cleaned off after soldering.

Your 'finger' should not 'work' now any more...

Dave
 
Nothing, again same issue...i have to check again in this zone.....probably the pin is not the cause.
 
Last edited:
It's arrived second Vectrex, tomorrow i open it, and check what version is it.... then try to connect logic of this on my monitor e vice versa
 
Hi at all, i have reworked this Vectrex about 1 year! Yesterday i have disassembled all boards and rechecked all, replaced all transistors, all 1n4148 diode and all diode inside the power board, i have found one resistor on output of Fyback with 3,3ohm when cold, but going to infinite when hot, replaced it now the image is better (my older problem are a full distortion image when cold and relatively good when hot but with a impossible regulation of DAC offset) , i have cleaned image with guide of regulations with DAC offset and all other, and i have centered it with magnet on yoke, then i have moved vertical and horizontal trimmer to set correct aperture of the screen.

Now with test 1 i have a good grid when cold, but after about 2-3 minutes the left part of screen going to collapse to the center of display, all lines collaps or have a flickering.

At this point i have sprayed cold air on the bottom side pins of IC401 LM379S, and.............when cold screen going to correct status, when i stop cold air again it going to collapse.

Probably i have a heatsink problem on LM379S, i have replaced it last year but, the little heatsink placed originally on the chip, with hole for screw for the big heatsink, it moves and the thermal glue are not good from chip and little heatsink and from this little heatsink and the big one!

Tomorrow i will check if i have a chance to fix the little heatsink on the chip and replace the thermal glue with a good one.

I think so this is the final problem to solve all other my problem.

I update post tomorrow.

Thanks
 
Good detective work. Let's hope that is the problem.

If not, it could be something around the IC like a bad solder joint, faulty PCB via etc.

Dave
 
Hello again Dave,

I have fixed the cooling problem of the LM379S, basically I disassembled the heatsink and I saw that the integrated fin on the chip had come off, so the whole large heatsink was cooling very little.This morning, however, before disassembling everything, I turned the Vectrex back on to see if it had maintained all the adjustments made yesterday, but unfortunately again I find myself all messed up, the grid completely confused, so I proceed to solve the collapse problem.

Taking advantage of the disassembly I removed this chip that I had already replaced last year thinking it was the culprit and I put its original back, this time however I first fixed the chip on the fin with the thermal paste in the middle and tightened the two screws that hold it and then I mounted the whole heatsink being careful when inserting it, now the screen no longer collapses from left to center.

But......but.....but ......I turn the Vectrex back on and nothing has changed about the initial problem, the grid is all messed up again, so it wasn't that resistance that I found strange, so I go to check the DAC offset and it was at 0 as I had left it, then I try to adjust the integrator offsets with the two trimmers but it can't be solved or fixed in the slightest, as it heats up it improves but not completely, some vectors are completely out of place.Just in case, I also reinserted the original CPU and tested 4 new 6522P, but nothing changes.Then I noticed this, if when the machine has been on for a few minutes I blow cold air in the area of the integration capacitors or around the MC34001 the image moves and tends to settle, almost perfectly.At this point I would say that I have no problems on the powerboard that I have practically changed everything except the resistors and the flyback, but on the logic board and certainly in the area just described, too bad though that I replaced the capacitors last year, it must be said however that these capacitors are not the ones supplied in the kits for sale online for Vectrex, I bought them elsewhere individually, of the same brand WIMAR and of the value for my model, I would not want them to not be suitable for some reason!

I could reassemble the originals if I wanted, which are not the polypropylene ones in my board. I checked the soldering, I went over the soldering both above and below, the 4066, the 4052m and the DAC 0808 were replaced, the others are all the originals because I can not find new ones (2x MC34001 and 1x MC34004).I don't know what to look at anymore, the power board is practically new, I also changed every transistor present, including the BU407, while on the logic board the two logics and the two RAMs remained, the rest is all original, I saw that there is still some dirt between the pins, I could think about doing a further wash, after which I just have to buy a kit of integration capacitors and hope to find the operational chips that remain from the vector management.

After that I just have to think that it is a problem with the flyback that can't take it anymore, the voltages are all perfect!

This Vectrex is really a mystery to me!
 
Hi Dave,

yesterday i have received new op amp with original type, 34004 and two 34001 and i have washed the board because the first cleaning have not removed all dirt... I have replaced op amp but the problem still the same, at cold all vector distorded and both trimmer for INTEGRATOR OFFSET stay one opposite to other for a best visual but not correct aspect too.

At this point i have suspected to the new integrator capacitor replaced last year. I don't have buyed a kit for VECTREX but i have replaced it with a normal WIMAR capacitor with same value, my model have three 0,01uF and three 0,0022uF, different to other vectrex with styrene capacitor and different value.. and if i spray cold air on it the vectore moves on screen then return at wrong position.

I have resoldered the original capacitor and..........at fist time power on i have a very nice image, not centered, not good calibrated....then i have recalibrated DAC offset and Integrator offset and centered image with two rings on the tube and enlarged image with two trimmers on the monitor analog board. And NOW if i spray cold air the vector dont move anymore, only little bit!

Now the image is very pretty and ok, i have turned off the Vectrex for 6 hours and then i have returned on, only a little change on image but after 3-5 minutes it's going ok ! And now the trimmers of INTEGRATOR OFFSET are calibrated to the same position and not one opposite of other and i have checked on other Vectrex and the position is the same!

Ok, the problem are located on INTEGRATOR CAPACITOR, probably any of six, or all six, are in lost value and when hot about 5 minutes going prefectly working... AND THE NEW BUYED RESULTS VERY VERY WRONG TYPE AND QUALITY probably..... my error.

Now i have to find new and good integrator capacitor, on console5 site are present all type but not for my 3GE model, only 0,01uF are ok but the site don't have the 0,0022uF....

A question: This capacitor is a particular type for the application? Have a particular construction material or any other differencies to the other one?
Where i buy alla new and compatibile with Vectrex?

At this point the machine is very new, all integrated circuit new, all diode new, all electrolityc capacitor are new, cleaned all, only integrator capacitor are old.

Tomorrow, or in next day, a post a little vldeo with the DEFLECTION PROTECTION test where i see a singolarity problem, all other test are very good and stable.
 
Last edited:
Sorry i have mistake, i have tested new and old op AMP and nothing change next to the correct calibration, this is a good notice because the problem are not on it, and not on a solder pads i have cleaned and checked one to one.
 
Can you post photographs of the original integrator capacitors?

From the markings on them, I may be able to locate the manufacturer and the part.

Dave
 
Hi Dave,

at this moment i have closed machine, but in post number 22 is present an image of original integrator capacitor on my board. And the situation the same of initial of threads on post number 59, particular on image 20231030_233805, the DEFLECTION PROTECTION test with the left vectors out of square! all other is nicely working, i have turned on after night and only a little change on settings but again after 5-10 minutes all going ok but not the DEFLECTION PROTECTION test!
 
Hi,

The trouble with the photographs in post #22 is that the full details are not readable on all of the capacitors. Although, once we have identified the manufacturer and type, the only difference would be the value.

Dave
 
You must log in or register to reply here.
Back
Top