ThatGuyUKnow

Hello all. V1 Game Gear. I’ve recapped the system. Screen was faulty. Replaced it with a CleanScreen. The sprite colors are wrong. I’ve already verified the LCD and CleanScreen are functional. I replaced the single asic, vram, and system ramZ the issue persists. Pictures of the graphical issue are attached. Suggestions?

Yeah I was thinking it must be a trace issue. Time to get to work with a multimeter.

I have an Atari Lynx II with no audio. Everything else on the handheld works correctly. I verified the speaker is good. I thought it might be the headphone jack so I swapped it out with a known good with no change. I thought it might be the volume taper so I switched that out with a known good with no change. The board needed new caps so I replaced the electrolytic capacitors with no change. The audio circuit is getting a proper 5V from VCC. I traced the circuit from pin 32 of the rom cart through Hayato to U7 and U12 checking all components for shorts on caps and checking resistor values but found nothing. I replaced U5, no change, U12, no change, U7, no change, Hayato, no change. I down to checking every trace in the audio circuit for continuity. Any advice or other troubleshooting suggestions?

I have 2 Lynx 2 consoles. Both have been recapped and the power systems refreshed. I installed BennVenn screens in both. I get a single blinking pixel ONLY in the Blue Lightning intro. It doesn’t appear in gameplay and doesn’t appear playing Shadow of the Beast at all. The pixel shows up in exactly the same place on both consoles. I’ve already asked Ben in his discord and he believes it’s a ram/Suzy issue. I would expect that if it was a ram or Suzy issue the pixel would be a consistent issue, but it’s not, it only blinks during the intro of Blue Lightning and goes away when the game starts. It’s a Rev 6B screen. I wanted to ask here to get second opinions.

I wanted to give an update in case anyone runs into a similar issue. I was doing research in the forum and found some posts by RJ1307 who gave information on using jumpers to bypass the flex and the cartridge to rule them in or out as issues. I did this and the system worked. I disconnected the one for the flex. It still worked. I disconnected the jumper for the cartridge (pins 31 and 33) and it no longer powered on even with a game installed. I cleaned the slot with 99% IPA and a nylon brush. I then used flux to Re-flow the pins for the cartridge slot. This fixed the issue. It’s obviously coincidental that I had done some work to the board as this issue was unrelated. This jumper method is a great starting point for any power related issues with the Lynx ii so you can determine if it’s a flex, cartridge, or power rail issue.

I misread the schematic. I haven't finished my EE degree and the way I read the schematic it looked like they were tied in because I over looked the op amp in u6 that the line clearly went into. *facepalm*I haven't done anything yet which is obviously good. Pin 7 of U6 has continuity to the ground rail. I tested continuity to both C42 and R71. Battery positive continuity to C36, From C36 to the base of Q7, through the transistor, collector continuity to TP18 and pin 13 of U6. Using the wall adapter, with the negative lead on pin 7 and the positive on pin 14 it starts around 4.5v and then rapidly falls to a low mV rating. Using batteries the power comes in pin 13 via Q7 the transistor has 9v on the base, 8.3V on the emitter and 45mV on the collector going into pin 13. The emitter leg is noted on the silkscreen and the data sheet shows the single pin as the collector. If I measure negative on pin 7 and positive on pin 14 it reacts the same way as with the wall adapter starting around 4.5v and rapidly falling down to a near 0 reading. Using the wall adapter I get 8.43V on the emitter of Q7 and 45mV on the collector. What I am questioning is, are the transistor readings correct?

Here is the lower part of the schematic. I forgot to upload this earlier.

In the process of replacing it I looked again at the schematic and for the purposes of continuity it shouldn't matter whether C52 is good or bad since it shows there should be a direct connection between Pin31 of the rom cart and the ground for the power rail which in this case I'm measuring from C35. If I'm reading the schematic correctly, I think the trace between C52 and C35 is not connected and I should run a wire. Do you concur on this assessment? I included the area of the schematic for quick reference.

Pin 2 continuity to L14, continuity to both sides of L14 inductor, L14 continuity to anode of D10, D10 anode continuity to D11 anode, D11 anode continuity to C35, C35 continuity to C37 ground, C35/C37 continuity to R68, no continuity to C52 (I can't pass voltage in diode mode, I pulled it off the board and it registers 0nF) Based on the schematic the line is Pin 31 (PWR4069) from the ROM cart. I do have the cart in while testing. I do have continuity from Pin 31 to C52. I'm going to replace C52 before doing any more testing and report back.

Yes those were voltages with the power plugged in, game inserted, and no power button pressed before measurements were taken. I thought the same thing regarding the U6 being faulty so I replaced it with a MC14069B U6 replacement chip from eBay. Still getting weird readings. double checked TP15 and with the AC plugged in I’m getting .450V. Regarding the power pins to the battery terminals, these were the DMM continuity/resistance readings with no power. - Batt Terminal. Pins 2+3 have direct connection .8 Ohms. OL for pin 1 + Batt Terminal pin 2 4.8M Ohms pin 1 2.3M Ohms pin 3 2.3M Ohms Looking at the schematic: I wanted to check the power rail. Continuity from pin 1 to anode. Using diode mode .555V anode to cathode, OL cathode to anode. I used the cathode as the continuity point for the rest of the power rail. Continuity to cathode of D11 .535V anode to cathode, 2.5V cathode to anode. Continuity to C35, C36, C39 positive, D12 cathode, continuity to C40, C41 positive, continuity to the emitter on Q8, continuity to R74, C44, and R75. Does anything stick out to you here or should I check through the ground rail? Jared

Yes it’s pointed to TP19. I tried with the zener shown on the board as well as the one that came with the Console5 set. Same result with both.

Hello all! I have an Atari Lynx 2 that was fully working before I replaced Q8/9 transistors, Q11 MOSFET and D1 zener with the Console5 set. The system will no longer power on. I injected 5V into C41 and it boots up correctly which tells me the issue is with the power system. It’s likely not relevant, but I did recap the system as well. I replaced the transistors, mosfet, and diode again with no change. Ive gone through some of the old forum posts to diagnose the issue and took some readings. Regarding U6: With the DMM common on Ground the readings are as 1: 0 2: 8.9 3: 0 4: 0 5: 8.9 6: 8.9 7: 8.9 8: 8.9 9: 0 10: 0 11: 8.8 12: 8.8 13: 0 14: 8.1 With Com on pin 7: 1: .453 2: 0 3: 0 4: Starts at about 1.7V then moves to about 200mV 5: 0 6: 0 7: COM 8: 0 9: 0 10: .457 11: 0 12: 0 13: Starts at about 2.6V then moves down to about .433V 14: .433 I checked the system with a thermal cam and didn’t find any hotspots. TP 15 is 0V. If I connect the drain and gate on the mosfet the system powers up. Thoughts?