Randy Posted December 8, 2020 Share Posted December 8, 2020 Not getting sound out of my TT. I notice there is a built-in speaker with a connector, not sure how this is supposed to be connected and if it interferes with the RCA jacks on the back. Any ideas or test I can try to get sound out of this? Thanks Quote Link to comment Share on other sites More sharing options...
MasterMotorola Posted December 8, 2020 Share Posted December 8, 2020 Randy, The speaker should not interfere with the RCA jacks. I disconnected my internal speaker but the below photo shows where it connects to the mainboard. If you are not getting any sound from the RCA jacks then first try a different cable and then check the volume settings in your control panel if you have that installed. Quote Link to comment Share on other sites More sharing options...
Bikerbob Posted December 9, 2020 Share Posted December 9, 2020 On 12/8/2020 at 2:58 AM, MasterMotorola said: Randy, The speaker should not interfere with the RCA jacks. I disconnected my internal speaker but the below photo shows where it connects to the mainboard. If you are not getting any sound from the RCA jacks then first try a different cable and then check the volume settings in your control panel if you have that installed. There is no way to turn the volume down on that internal speaker is there? Late at night on the TT030 those key presses and the bell ring sound massive. Dont really want to disconnect it total, but lower would be nice. OH well. Read your signature MasterM, that is one crazy sounding TT030 you have there. WOuld love to see pics etc.. on it. Specs? whats in it? James Quote Link to comment Share on other sites More sharing options...
Randy Posted December 9, 2020 Author Share Posted December 9, 2020 Thanks, but I don't think this is the problem, I am getting zero sound from this so I think it is more of a hardware problem. I found a similar post about a Falcon having the same sound issues, so I am going to try using that repair stratagem for getting sound back on this TT. Originally, this TT had a blank screen, the roms were in backwards so I fixed that but after a time, the blank screen, or more properly, no video out, came back as an issue. A thorough cleaning and recapping of the motherboard and PS seems to have solved that issue as well as three broken ceramic caps found that were replaced. The HD floppy is not quite working/reading disks, so I need to get that right as well. Quote Link to comment Share on other sites More sharing options...
mpattonm Posted December 10, 2020 Share Posted December 10, 2020 Check 12V output of the PSU. Quote Link to comment Share on other sites More sharing options...
Randy Posted December 10, 2020 Author Share Posted December 10, 2020 2 hours ago, mpattonm said: Check 12V output of the PSU. thanks patton, will do. I know that the ps was supposed to have been an issue before Quote Link to comment Share on other sites More sharing options...
Randy Posted December 12, 2020 Author Share Posted December 12, 2020 Check the 12v, it's good. I am however, getting just 8.3 v on the V+ of the LM1992 chip which seem to be where the sound is to be generated though. This was also the area where several ceramic caps were damaged. Quote Link to comment Share on other sites More sharing options...
Randy Posted December 12, 2020 Author Share Posted December 12, 2020 Just now, Randy said: Check the 12v, it's good. I am however, getting just 8.3 v on the V+ of the LM1992 chip which seem to be where the sound is to be generated though. This was also the area where several ceramic caps were damaged. oops, just check the schematic, looks like 8.2 v is good for that chip... Quote Link to comment Share on other sites More sharing options...
Randy Posted December 14, 2020 Author Share Posted December 14, 2020 OK further checks have given me the following. First, the internal speaker has a 57 ohm resistance, that sounds totally BS, I have never seen a speaker with that kind of impedance/resistance, so I am thing the internal speaker is bad, however that should not affect the RCA outs. Mentioned was the voltage on the LF147 op amps, one has the +- 5v, however the second one has +8 and -4 volts, so that is wrong, maybe blown when the roms were put in wrong? At any rate, I'll replace that one, but I should note, those two op amps feed the signal going into the on-board speaker and would not affect the output to the RCA unless I am missing something. What do you guys think? Quote Link to comment Share on other sites More sharing options...
Randy Posted December 20, 2020 Author Share Posted December 20, 2020 OK, continuing to work on the sound issue with no luck. Anyone use the Atari diag cart to test the sound system on the TT? Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted December 20, 2020 Share Posted December 20, 2020 I'm pretty sure you can use the Sound CPX module to turn the sound down on the internal speaker or turn key clicks off altogether. HTHs. Quote Link to comment Share on other sites More sharing options...
Wally1 Posted December 20, 2020 Share Posted December 20, 2020 (edited) I did not know there was an internal speaker on any ST variant. Are there any other makes with said same? Is it a nice feature? How does it compare to the 8bit gallery (i.e. 400, 800) with their internal speakers? To me, that was a huge plus. Edited December 20, 2020 by Wally1 Quote Link to comment Share on other sites More sharing options...
Chri O. Posted December 21, 2020 Share Posted December 21, 2020 Honestly I think you have issues with LMC1992 IC, tone -bass -treble- volume Control. ATARI TT sound capabilities looks similar to ATARI Ste platforms (Yamaha YM2149 + DMA DAC + National LMC 1992, same as in STe), I am hoping this DEMO plays through the TT/STe DMA+DAC output ? No idea if this works but you should try this DEMO: Alfons' Greatest Samples Part 4 by Delta Force https://ftp.untergrund.net/users/ltk_tscc/fujiology/ST/D/DELTA4CE/ALFONS_4.ZIP FROM: https://demozoo.org/productions/81588/ See if you can get sound from (DMA DAC) Digital-to-analog converter. 1 Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted December 21, 2020 Share Posted December 21, 2020 11 hours ago, Wally1 said: I did not know there was an internal speaker on any ST variant. Are there any other makes with said same? Is it a nice feature? How does it compare to the 8bit gallery (i.e. 400, 800) with their internal speakers? To me, that was a huge plus. As far as I know, the TT030, STacy, and Falcon all have internal speakers. The STacy only has that for sound unless you plug in an external monitor then it uses the monitor's speakers. It's okay, but definitely not made by Bose, if you know what I mean. The TT and Falcon of course, have the stereo RCA out for great sound, IMHO (besides the internal one) I'm not sure how they compare to the 8bit version. Didn't the later models drop the internal speaker on the 8bits? I was under the impression that the early internal speaker was for key clicks and single tones. Is that not right? Thanks. Quote Link to comment Share on other sites More sharing options...
mimo Posted December 21, 2020 Share Posted December 21, 2020 1 hour ago, DarkLord said: I'm not sure how they compare to the 8bit version. Didn't the later models drop the internal speaker on the 8bits? I was under the impression that the early internal speaker was for key clicks and single tones. Is that not right? Thanks. yes, the internal speaker was only on the 400 and 800 models and was dropped for the XL. Correct, the key clicks and the beep when booting holding start to load a cassette was through the internal speaker, this then moved to the external audio for the XL and XE line Quote Link to comment Share on other sites More sharing options...
Randy Posted December 21, 2020 Author Share Posted December 21, 2020 10 hours ago, Chri O. said: Honestly I think you have issues with LMC1992 IC, tone -bass -treble- volume Control. ATARI TT sound capabilities looks similar to ATARI Ste platforms (Yamaha YM2149 + DMA DAC + National LMC 1992, same as in STe), I am hoping this DEMO plays through the TT/STe DMA+DAC output ? No idea if this works but you should try this DEMO: Alfons' Greatest Samples Part 4 by Delta Force https://ftp.untergrund.net/users/ltk_tscc/fujiology/ST/D/DELTA4CE/ALFONS_4.ZIP FROM: https://demozoo.org/productions/81588/ See if you can get sound from (DMA DAC) Digital-to-analog converter. Hi Chri, I am going to try and see if I can read an output from the YM chip when pressing the keyboard, I was told that the YM chip will output when the keys are depressed. Your suggestion is also good, using that demo to check output from the DMA chip, but I am feeling the same as you, that the issue is probably with the 1992 chip as it is common to both the YM and DMA chip, everything has to pass through there. I have tried to run "Fire and Ice" game and absolutely no sound at all, not sure if that game uses the DMA chip though. Thanks! Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted December 21, 2020 Share Posted December 21, 2020 8 hours ago, mimo said: yes, the internal speaker was only on the 400 and 800 models and was dropped for the XL. Correct, the key clicks and the beep when booting holding start to load a cassette was through the internal speaker, this then moved to the external audio for the XL and XE line Thought so. Didn't a few creative people still come up with ways to play (simple) music through it? PS Also, we're way off topic here. Quote Link to comment Share on other sites More sharing options...
Wally1 Posted December 21, 2020 Share Posted December 21, 2020 yes see xxl's work for the int. chiptune music not so shabby either! Quote Link to comment Share on other sites More sharing options...
Randy Posted December 25, 2020 Author Share Posted December 25, 2020 On 12/21/2020 at 12:17 AM, Chri O. said: Honestly I think you have issues with LMC1992 IC, tone -bass -treble- volume Control. ATARI TT sound capabilities looks similar to ATARI Ste platforms (Yamaha YM2149 + DMA DAC + National LMC 1992, same as in STe), I am hoping this DEMO plays through the TT/STe DMA+DAC output ? No idea if this works but you should try this DEMO: Alfons' Greatest Samples Part 4 by Delta Force https://ftp.untergrund.net/users/ltk_tscc/fujiology/ST/D/DELTA4CE/ALFONS_4.ZIP FROM: https://demozoo.org/productions/81588/ See if you can get sound from (DMA DAC) Digital-to-analog converter. OK, finally got back to this one. Was able to read keyboard presses on the output of the YM chip and those same pulses into the 1992 chip, but there is no corresponding output from the 1992, so that doesn't sound good! Vcc is present, don't see a clock pin for this chip, is there a clock pin on teh 1992? Quote Link to comment Share on other sites More sharing options...
Chri O. Posted December 25, 2020 Share Posted December 25, 2020 4 hours ago, Randy said: is there a clock pin on teh 1992? NO, there is however clocking signal on pin#2 for the three-wire communication interface (LMC1992 microwire interface). Happy Holidays all. Quote Link to comment Share on other sites More sharing options...
Chri O. Posted December 25, 2020 Share Posted December 25, 2020 (edited) LMC1992 microwire interface (pin#3 ENABLE, pin#2 CLOCK, pin#1 SERIAL_DATA input). LMC1992 Datasheet: http://m.www.datasheets.pl/elementy_czynne/IC/LMC1992-3.pdf Edited December 25, 2020 by Chri O. add link Quote Link to comment Share on other sites More sharing options...
Randy Posted December 25, 2020 Author Share Posted December 25, 2020 Thanks Chri, got the datasheet down last night after I asked the question and saw the clock is pin 2, although not connected to the clock line. At this point, seems likely a bad 1992 chip, now just need to locate one to replace the one in my TT and give that a go. Quote Link to comment Share on other sites More sharing options...
Randy Posted January 17, 2021 Author Share Posted January 17, 2021 OK, finally got back to this after the replacement 1992s came in, pulled out the old one, put in a socket, and, nothing (at first..). But when I was checking around the next day I noticed output on 14/16 and of course the RCA jacks, woowee, its working! Put it back together piecewise and tested at each stage, still working, until I put back on the VME bus shield and the internal speaker (did that at the same time). Sound totally died again, WTF! I have been checking it since then, still the same issue, audio out from the YM chip is good into pins4 and 26, but nothing on pins 5 and 25, which is a part of the voltage divider off f the 8.2 v rail, which does show that all four pins have DC offset and of course the 8.2 v is at pin 28. Not sure what happened to make the sound die, tried both 1992 chips but still nothing. I am guessing at this point that the 1992 is not the fault, but something else is going on, I did notice some dried yellow substance near pins 5-9 that cleaned up, maybe a cap leak, but that and all other caps have been replaced and there does not appear to be any corrosion or trace damage. Any suggestions? Thanks. Quote Link to comment Share on other sites More sharing options...
Chri O. Posted January 19, 2021 Share Posted January 19, 2021 (edited) On 1/17/2021 at 1:00 PM, Randy said: until I put back on the VME bus shield and the internal speaker Try removing the VME bus shield and try again ? I'm looking at the Atari TT datesheets (Page#24) and I noticed this: 2,4.10 VMEBUS The VMEbus is provided to allow for system expansion and conforms to industy standard VMEbus revision C.1. Interrupts IRQ1-IRQ7 are interfaced and arbitrated through the SCU chip. A global 16 MHz clock is provided to the VME bus via the TTVIDEO chip and a74LS44latch. This provides total independence of the clock from the processor speed. A 24-bit address bus, l6bit data bus, and control signals are provided to the VMEbus via the MC68030. This configuration causes the main system board to act as the VMEbus controller when a card is installed in the bus slots. The Atari TTVIDEO also controls the LMC1992 microwire interface I'm wondering if there's any type of short on the VME bus shield ? Edited January 19, 2021 by Chri O. 1 Quote Link to comment Share on other sites More sharing options...
Randy Posted January 19, 2021 Author Share Posted January 19, 2021 Hmm, this could be the issue, I did remove the shield and speaker and there still is no sound. Using an 1040 STe, which has the similar audio system, i.e., a 1992m I went through and check all the voltages and pin signals and correlated between the two systems, all of the signals except for the output signals on the TT 1992 were the same, the DC voltages were close except for the split voltage between 4 and 5, they are not exactly the same values, which they were on the 1040 STe, where 4 and 5 are the same value, the TT is off by about 0.7 Vdc which is strange since the 8.2 is divided exactly by the parallel voltage divider circuits. It may be that I blew the 1992 when I powered the TT up with the VME shield in place, is that possible? Thanks Cri! Quote Link to comment Share on other sites More sharing options...
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