Brik_1111
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Posts posted by Brik_1111
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I just want to take a second to thank you for your patience and ongoing help, Taijigamer. Evidentially, this repair is challenging me quite a bit so I appreciate the ongoing assistance.
I measured the crystal directly and even though I got a fairly erratic signal (which I think is down to my cheap-o oscilloscope) it seems to range close to 16 KHz instead of MHz. Could be to do with the scope itself or the way I'm using it. This is my first time using a scope for a repair.
I gave pin 19 a splash of fresh solder but I still get the same result - it shorts when I try to test it (and the audio cuts out). I beeped out where it's supposed to go and everything checked out. Just to clarify, I can attach the ground probe to any ground on the board? And then touch pin 19 with the positive probe to get a reading? As I said, it could be user error on my behalf since I'm so new to using a scope. I'm using the same settings to do this as the image above when I directly test the crystal (although in that case I'm touching each probe to each side of the crystal).
As for the XACLK line, a waveform does measure between pin 19 and 129 of the CLEO (again, one scope probe on each end). Whether it's the right one, I'm not sure. The pins on the CLEO are so tiny, it's hard to just get a reading on the one pin lol. I also checked the continuity along XACLK and everything seems cherry.
Following on from that, I read further into the troubleshooting diagram and (I think) I successfully measured between the AUDBCK, AUDWS and AUDDAT lines back to IC200.
As for C201 and 202, I was unable to find a way online to test ceramic SMD caps. What I do know is that they have continuity going to the right places and using the diode test on my multimeter I know they're not shorting to ground. I desoldered one to test out of circuit but my meter measured nothing in capacitance mode. I don't think it goes down as far as picofarads.
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C36 and 36 are definitely good. They've been replaced and I beeped them both out.
I'm pretty new to oscilloscopes but when I test pin 19 of IC200 (as per the troubleshooting guide) I get absolutely nothing, close to 0v (and no waveform). It actually seems to short-circuit as the audio cuts out completely when I test the pin.
Do you think this indicates that the crystal is bad? I've been trying to suss a replacement but all my local electronics store has is a 16Mhz with an ESR of 25ohms. I can't figure out the ESR of the original and it's been rated at 16.9-something MHz instead. Would it still work?
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Replaced the transistors today. While it didn't break anything (thank the gods) the sound is still distorted. Any other ideas? Any tips on troubleshooting IC200?
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I bought some other stuff and got free shipping haha. I see what they did there...
Anyway, the transistors have been ordered. I'll let you know how it goes.
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I have a very basic oscilloscope that cost something like $30 from China haha - so for now, I think I might just be easier to replace them and see what happens.
Thank you for finding those modern equivalents. I spent ages yesterday researching how to read transistor codes and never figured it out. I'm a bit confused by the TA and TC codes, however. In the datasheets you linked TC is PNP while TA is NPN, which is backwards to your explanation of the codes and the original parts list:
Just to clarify, Q270 is PNP and Q220/240/260 is NPN right?
With that in mind, I found these in stock that ship to down-chunder (with $24 shipping 🙄 ). Can you please double-check they're the same thing:
NPN Q220/240/260: https://www.digikey.com.au/product-detail/en/diodes-incorporated/DDTC114TCA-7-F/DDTC114TCA-FDICT-ND/815570
I noticed that when you check the datasheets in those Digikey links (which are the same) it's the opposite again to what's on the sale page. Maybe the datasheets are incorrect? Confusing.
Also, I do believe the original transistors are SOT-23. I measured them yesterday with callipers and crossed checked them with a chart.
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An update: I borrowed a working CD-ROM drive and the audio plays, but distorted. It turns out the screensaver was mute because pressing the A button toggles the audio on/off (which I discovered by accident). Any clues on the distortion? Would the transistors still be a focus point? I haven't figured out how to test them yet as per the troubleshooting guide. I also spent all afternoon checking the continuity of the caps I just replaced, so I'm happy they're not the problem.
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Yep, testing with my logic probe and the base and collector are high and low respectively. Side note: How do you determine what's the emitter, the base and the collector? I found a few conflicting diagrams that swap the base and collector around (Q270 is PNP, right?).
With those testing okay, the next section of the troubleshooting chart says to replace Q220 and check Q240 and Q260. What constitutes as "checking" them? Sorry if this sounds basic, but if anything this is a good learning project for transistors for me ha.
As for replacing Q220, the parts list in the Service Manual lists a parts number of DETC114TKT97 (transistor, resistor built-in) and is the same as Q240 and Q260. Any clues for a suitable, modern replacement? DETC114TKT97 appears to be a Panasonic only parts number and I'm struggling to find a specs sheet.
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I recently bought a dead 3DO back to life by replacing the transformer. I'm in a 240v region but since it's a US model, someone plugged it in just using a travel adapter and fried it.
It now boots up fine and the comet screensaver plays, but it's completely mute. I just finished a recap using a kit from Console5 but the issue remains.
I'm trying to follow the Audio Check flowcharts in the technical guide that's floating around, but I'm struggling to make heads and tails of it. My knowledge of transistors is limited and I think the guide might be for the UK and Canadian variant - I can't locate Q240 and Q260, for instance.
As a side note, I plugged headphones into the controller and can sort of hear the ghost of loud sounds (like when a comet flies past the screen), but it's very low and distorted. I'm testing using composite and have also tried RF - but I can only hear static.
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Quick question: Does it matter which specific wires of the blue connector go to pins 6 and 10? Either way around is okay?
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34 minutes ago, Taijigamer said:The data sheet says to connect your mains cable to pins 1 & 5. Connect 2&4 together. On the output, connect your blue connector cable to pins 6 & 10. Connect your red cable to pin 8.
https://imgur.com/gallery/a0AdRrn
Thanks Taijigamer, you've been a tremendous help. I'll order one in and report back once it's installed and (hopefully) working.
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6 hours ago, Taijigamer said:Sorry, just checking you probed the voltage between the pins (blue connector) and not between each pin and ground (red connector).
What voltage does your region use, 110V or 240V?
Yep, just probed the blue connector with a probe on each pin. We're 240v here in Australia, but I've been using a step down transformer so far for testing.
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3 hours ago, Taijigamer said:That’s correct, probe both pins on the blue connector (+ on one pin and - on the other). If the transformer is working, you should get 10 - 18VAC. If it’s lower than 10 VAC the transformer is faulty and needs replacing.
Confirmed, less than 6v measured. Guess I'm buying that replacement from the other thread. Can offer any tips for wiring this? Looking at the spec sheet, which tabs do the blue and red wires connect to?
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11 hours ago, Taijigamer said:Did you check the 2 pins on the transformer output (probe to pin, not connected to board)? If it’s still low voltage it sounds like a problem with the secondary winding inside the transformer. In which case check that other thread for recommendations for replacing the transformer.
Do you mean any of these two connectors disconnected from the board? Where do I probe for ground? Excuse the ignorance, I don't have much experience with AC.
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Hi all, apologies for the lengthy post but there’s a bit to explain.
I recently received a broken FZ-1 that won’t turn on. From what I can tell, at least two others have been inside before me, which is never good. The power cable had been previously cut, with the copper simply twisted together and held with electrical tape.
Capacitors 1, 35 and 36 had been replaced but with substandard soldering. While the pads were connecting to where they needed to go, the solder was dull and bumpy. Additionally, D2 was missing completely with R2 extremely corroded.
So, I got to work properly repairing the power cable, soldering the copper together and covering the breaks with heat-shrink. I redid the caps even though there was continuity, replaced R2 and also D2 using a modern replacement suggested on this Russian forum (eighth post from the bottom).
As you can see in the photos, the positive pad for C36 is a bit destroyed. There’s still continuity, however. At this point, the console still wasn’t turning on, so I started reading the service manual and technical guide. Following the flowchart on page 5-2 of the technical guide, I determined that the power switch was shorting as it’s supposed to when on/off and that the fuse was good.
The next section of the flowchart asks if AC 10-18V is being outputted to both CN1 terminals – and it turns out that’s not the case. I measured only AC ~0.23V on both. Is this the smoking gun? I’ve never worked on a 3DO before. In fact, I’ve never checked AC on anything. I simply switched my multimeter to AC mode and checked the pins on CN1 while holding the negative probe to ground. Is that the correct procedure?
On further chat with the guy who gave me the console, he thinks 240v may have been put through the system before he got it since we’re in Australia (the console is American). What does everyone think? Could it be that the PSU is rooted having had 240 put through it? Is there another way to check it besides from CN1? And if it is, does anyone have experience replacing these? I read this thread that talked about replacing the 110v one with a modern 240v equivalent. I should add that I’m of course testing with a step-down transformer.
Alternatively, could the problem be something I’ve missed completely? Any input would be appreciated. Cheers.
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Hi everyone. I've been working on this broken 2600 Junior for the last week and since my huge amounts of research usually lead to this forum, you guys seem like the perfect bunch to ask since I'm now stuck.
A bit of backstory: I believe this Jr. encountered some tough times as the RF shield is very rusty. It turned on, but only tuned to a black screen. So on opening it up, the board was a bit messy but it did clean up quite well using isopropyl and white vinegar. I also reflowed a bunch of solder joints that were looking a bit dull, but this didn't change anything.
Just to clarify, the equipment I'm using to test this Atari (RF cable, game, power adaptor etc) have been confirmed with another working 2600 Jr I own. So, this rules out anything external - the problem lays somewhere in the Atari itself.
Onwards with the research, I learnt that the power regulator is prone to failure. Reading the pins, 9.03v was measured on one although the other measured at 4.93v - pretty low. So, I replaced that and it now read 4.98v and 9.06v - much better! The 2600 still wasn't working, however, now showing a colourful garbled mess of static instead of a black screen.
I then checked a few voltages over the board. 4.98v was tested going to the cartridge slot, the TIA, the RIOT 6532 and the CPU 6507. I also confirmed continuity to those chips by measuring between their Vss's and the ground pin of the vreg. This tells me the chips are powering on (I'm assuming 4.98v is adequate) but I do not own an oscilloscope to test that they're behaving as they should. For what it's worth, neither get too warm while the console is operating.
Hoping that it's not any of the chips that are the problem, I scoured the board for anything that seemed out of place. Two components stood out to me; C38 and R43. The legs on both were corroded and the pads below were a bit of a mess.
I have no means of testing the cap, but the resistor (when removed) measured about 8.8K oms, while according to the schematic it's supposed to be 9.1K. That was replaced easily enough, while the cap was replaced with a 0.1uF ceramic disk type - a recommendation I found in this thread:
Here are some photos of the replacements soldered in. They soldered in fine from the bottom of the board, but do you think the pads on the top are too corroded? I couldn't get any solder to stick. I'm not sure if they connect to traces on the top or not and if a connection is being severed.
If it helps, here are a few more photos I took of the board overall.
Thanks for reading. I look forward to your answers!
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Cheap DIY 2600 Junior Select & Reset Tactile Momentary Fix
in Atari 2600
Posted
Apologies for bumping this thread again but I just want to chime in and say that while I successfully completed this mod (and a big thank you for posting it
) my switches were also too high for the stock buttons. So, I created and printed my own! I've made them freely available for download here: https://www.thingiverse.com/thing:4824351
I printed using ABS and they came out quite well, although I'm sure PLA would be fine too. They are a bit loose fitting but get the job done - I'll probably hone the design in the future.