I had a carbon resistor in an audio amp fail in such a way that it was behaving as a nearly perfect white noise generator. The ohms still measured correct, but it was really noisy in circuit. Gotta love old electronics. They can behave in ways that should not be physically possible.
Great video. As a novice I found the explainations, attention to detail and delivery style all to be excellent. Thanks for your time. Subscribed & notified
Nice job, all items working well. I had a job getting my NES going as someone had cut the IRQ line on the board. They added a wire to join it up again but didn’t realise they cut the line next to it. I added another wire to rejoin that line, cleaned the 72 pin socket and all was well. Good fun for $5 at a charity shop.
I really, really, like your channel,, it helps me alot on things, that are not the norm...most of the time..You dont give up...i can see that...which is the way I am also...I get no sleep thinking about what I cant fix...If you repair something, even tho it is not what your working on...your method helps alot...thanks..
Min 16 intermittent resistor. Yes I have seen another similar issue when working in the lab, back in 1980. A precision (Salmon pink) was showing its true value or nothing. I watched this for a few days on my meter after the excellent engineer (Gary) took 3 days ro find it ! Just out of interest, I found a 5.7V Zerner that read 5.85V in circuit. Not easy to get to, it was on the timebase board of a Telequipment D75 with a trigger pre amp issue. On the curve tracer tthe Zener turned on at exactly 5.7V, then on current transfer it split into several traces at 5.85V ! Up to then, noone has seen that, left the bench soon after so havent been able to see if anyone else has seen it.
Pull on the resistor and it will have the one cap fall off. The internal ceramic has cracked just inside the crimped on end, and the only thing holding it together is the paint and the force of the cap.
>worries about replacing socket since it could lead to stress on the board >puts enough pressure on the board to make it temporarily bend hmm either way nice repair video, your friend is lucky that so much of it was already close to working.
Excellent repair video! I have had a similar problem with a carbon resistor which read a much higher resistance than it should have but it broke in two on my removal attempt, which just confirmed that it must have had an internal fracture which was causing the high resistance reading. Although I don't always suspect resistors to be faulty I never totally rule them out, as such complacency will inevitably lead to frustration in the long run! I suspect your resistor had a similar internal fracture or manufacturing fault which caused the resistance to vary with thermal expansion and the paint kept hidden from view.
The carbon coating probably developed several internal micro cracks, causing intermittent contacts due to expansion and contraction when heat is applied.
All arcade monitors get the RGB signals from the arcade games mother board which has a DAC circuit that converts the PROMs output digital signals from the Color PROM chip into RGB signals for the arcade monitor. The Horizontal counter sync signals and vertical sync signals get combined/merged with the RGB signals. How does the CRT beam convert the RGB signals and sync signals into drawing the graphics on the CRT beam? The H&V sync signals are the CRT screen coordinates and the RGB signals are the color type, color tint, color contrast.
A raster display sweeps the three beams in a grid pattern across the display continuously synced to the H/V signals. To light up a pixel you have to wait for the beam to reach the desired screen coordinate and then send the RGB intensity values. This can be done with discrete logic, but a video chip is definitely advisable.
I think the resistor internal cracked or burned. This increases the resistance . Just for fun, I once took a ww resistor and scrape d away the coating. The resistance started to get up a lot for a few hours.
Is the resistor trying go open? The carbon comp in it might be starting to disintegrate, turning it into an old-school carbon microphone. Good work tracking it down...resistors are usually the last things to suspect.
Hi Artie, can you provide some feedback on acceptable substitute transistors for the TIS98 preamp (which are obsolete). I'm not sure what current and voltage thresholds are relevant to this circuit. Is an MPSA05 or a 2N2201 or 2N2222 more appropriate than the other? Which spec(s)Vebo/Vceo/Vcbo/Ic are critical (if any) in determining an adequate replacement? Would love to hear your analysis. Thanks for the great videos you produce, they are very instructive for a hobbyist like myself.
Just rewatched this excellent video, noticed there is a peculiar tip on your HV probe. Mine is comical and likes to slip out from under the anode cup. What is the flat angled tip on yours called? I’d like to add this to my tool chest.
What video chips does more raster arcade monitors use to convert the RGB signals to the CRT beam? Any differences in different raster arcade monitors or are all the use the same raster sync signals
Excellent. Nothing is more relaxing than watchinng somebody else do the work. :-)
I had a carbon resistor in an audio amp fail in such a way that it was behaving as a nearly perfect white noise generator. The ohms still measured correct, but it was really noisy in circuit. Gotta love old electronics. They can behave in ways that should not be physically possible.
The way you homed in on the digital fault was seriously impressive.
Great video. As a novice I found the explainations, attention to detail and delivery style all to be excellent. Thanks for your time. Subscribed & notified
Impressive deduction of repair ! Thanks
Thanks again for making this. Resistors are something I never think of when troubleshooting. I will start checking them the next time I fix something.
Excellent work. I'm sure those extra Asteroids boards will be valuable to someone to resurrect a machine.
Nice job, all items working well. I had a job getting my NES going as someone had cut the IRQ line on the board. They added a wire to join it up again but didn’t realise they cut the line next to it. I added another wire to rejoin that line, cleaned the 72 pin socket and all was well. Good fun for $5 at a charity shop.
I really, really, like your channel,, it helps me alot on things, that are not the norm...most of the time..You dont give up...i can see that...which is the way I am also...I get no sleep thinking about what I cant fix...If you repair something, even tho it is not what your working on...your method helps alot...thanks..
Min 16 intermittent resistor. Yes I have seen another similar issue when working in the lab, back in 1980. A precision (Salmon pink) was showing its true value or nothing. I watched this for a few days on my meter after the excellent engineer (Gary) took 3 days ro find it !
Just out of interest, I found a 5.7V Zerner that read 5.85V in circuit. Not easy to get to, it was on the timebase board of a Telequipment D75 with a trigger pre amp issue. On the curve tracer tthe Zener turned on at exactly 5.7V, then on current transfer it split into several traces at 5.85V ! Up to then, noone has seen that, left the bench soon after so havent been able to see if anyone else has seen it.
Pull on the resistor and it will have the one cap fall off. The internal ceramic has cracked just inside the crimped on end, and the only thing holding it together is the paint and the force of the cap.
Well done! This channel so deserves more subs and views
>worries about replacing socket since it could lead to stress on the board
>puts enough pressure on the board to make it temporarily bend
hmm
either way nice repair video, your friend is lucky that so much of it was already close to working.
Excellent repair video!
I have had a similar problem with a carbon resistor which read a much higher resistance than it should have but it broke in two on my removal attempt, which just confirmed that it must have had an internal fracture which was causing the high resistance reading. Although I don't always suspect resistors to be faulty I never totally rule them out, as such complacency will inevitably lead to frustration in the long run!
I suspect your resistor had a similar internal fracture or manufacturing fault which caused the resistance to vary with thermal expansion and the paint kept hidden from view.
The carbon coating probably developed several internal micro cracks, causing intermittent contacts due to expansion and contraction when heat is applied.
Nicely done!
All arcade monitors get the RGB signals from the arcade games mother board which has a DAC circuit that converts the PROMs output digital signals from the Color PROM chip into RGB signals for the arcade monitor. The Horizontal counter sync signals and vertical sync signals get combined/merged with the RGB signals. How does the CRT beam convert the RGB signals and sync signals into drawing the graphics on the CRT beam? The H&V sync signals are the CRT screen coordinates and the RGB signals are the color type, color tint, color contrast.
A raster display sweeps the three beams in a grid pattern across the display continuously synced to the H/V signals. To light up a pixel you have to wait for the beam to reach the desired screen coordinate and then send the RGB intensity values. This can be done with discrete logic, but a video chip is definitely advisable.
I think the resistor internal cracked or burned. This increases the resistance . Just for fun, I once took a ww resistor and scrape d away the coating. The resistance started to get up a lot for a few hours.
Is the resistor trying go open? The carbon comp in it might be starting to disintegrate, turning it into an old-school carbon microphone. Good work tracking it down...resistors are usually the last things to suspect.
Hi Artie, can you provide some feedback on acceptable substitute transistors for the TIS98 preamp (which are obsolete). I'm not sure what current and voltage thresholds are relevant to this circuit. Is an MPSA05 or a 2N2201 or 2N2222 more appropriate than the other? Which spec(s)Vebo/Vceo/Vcbo/Ic are critical (if any) in determining an adequate replacement?
Would love to hear your analysis.
Thanks for the great videos you produce, they are very instructive for a hobbyist like myself.
Just rewatched this excellent video, noticed there is a peculiar tip on your HV probe. Mine is comical and likes to slip out from under the anode cup. What is the flat angled tip on yours called? I’d like to add this to my tool chest.
i starting to miss my games now.
What video chips does more raster arcade monitors use to convert the RGB signals to the CRT beam? Any differences in different raster arcade monitors or are all the use the same raster sync signals
that resistor i suspect came too close to an asteroid and got toasted
ARTIFACT ELECTRONICS
vector ARCADE games have register files LS670 chips. What does these Register Files IC chips do in vector arcade games?