Sign in   |  Join   |  Help

Search

  • Re: Beomaster 8000 Restoration

    Yes Sonavor...This is my destressing activity..so have been buying tools on need basis. I did use a DMM to test the transistors and followed the general guidelines for testing a NPN and PNP transistors. I did pull out my component tester and tested all the transistors. None of them came up as "damaged component". TIP 141 - hFE - 36/35/35 ,Ube - 996/996/970mV, Ic - 5.6/5.6/5.6mA, CE - 578/570/567mV TIP 146 - hFE - 27/35/31,Ube - 873/858/862mV, Ic - 5.7/5.7/5.7mA, CE - 587/575/582mV
    Posted to General Discussion & Questions (Forum) by dahiyas on Tue, Nov 24 2020
  • Re: Beomaster 8000 Restoration

    I did pull out the transistors. All of them read 2.5v-2.8v between B-E instead of OL. Have ordered replacements. Hopefully will be here by weekend. What are the other components I should be checking on the output PCB ?
    Posted to General Discussion & Questions (Forum) by dahiyas on Tue, Nov 24 2020
  • Re: Beomaster 8000 Restoration

    Yes, I had replaced all the caps on all the boards. After finishing the setting of left, I looked at the right side. I noticed that the heat sink was hot. So adjusted the idle current trimmer and also the volume offset . switched off the system and waited for 10 mins. The heat sink was cool again. Switched on the system. The heat sink did not become hot but felt heat from the output pcb. switched off again. Both the BF857s were hot. Playing source through TP1, produced good sound from left but very
    Posted to General Discussion & Questions (Forum) by dahiyas on Mon, Nov 23 2020
  • Re: Beomaster 8000 Restoration

    Sonavor - Good news and bad news . I couldn't resist connecting speakers Looks like the left output pcb survived (the one I was trying to adjust and saw smoke). I connected penta (minus the amp) and left side plays well. But the right side is bad. I can hear low volume from the right side with distortion. The volume keeps fading out and coming back. Either this pcb was bad prior to me getting the system or while I was focused on the left pcb, the right pcb would be heating up if idle current
    Posted to General Discussion & Questions (Forum) by dahiyas on Sun, Nov 22 2020
  • Re: Beomaster 8000 Restoration

    No problem. I bought this used and the only thing working when I started was the standby light. After the recap I had plugged in headphones and that worked fine. (except the clicking on volume change - volume offset needs adjustment). I have changed the connectors on the cpu/display board and that has fixed the intermittent standby/display issues. I will proceed to checking the transistors. Don't have the external power supplies but we'll come to that later. Thanks again for the inputs.
    Posted to General Discussion & Questions (Forum) by dahiyas on Sun, Nov 22 2020
  • Re: Beomaster 8000 Restoration

    Thanks Sonavor.. 56.9VDC and 14.96VDC..so voltages were good. Closer inspection of the connectors revealed the issue. Connector p54 was not inserted properly. The plug was off by 1 pin and pin 1 was not connected. reseated the plug properly. No load current was showing -5.6mV. Started adjusting the trimmer (slowly) and the reading kept jumping between the -5.6mV to 18mV. The number kept on fluctuating. And then there was smell of overheating and a bit of smoke from the heat sink area. I quickly switched
    Posted to General Discussion & Questions (Forum) by dahiyas on Sun, Nov 22 2020
  • Re: Beomaster 8000 Restoration

    I changed the trimmers on the output boards and the tone control board. Adjusted the offset output to 0V across speaker outputs. Two issues - 1. I am not able to adjust the no-load current. The reading across R236/R237 always shows 0, adjusting R226 has no impact on the reading. 2. The "Offset Volume Control" instructions require a oscilloscope and I don't have one. Can I do this without a scope ? Any suggestions ?
    Posted to General Discussion & Questions (Forum) by dahiyas on Sat, Nov 21 2020
  • Re: Beomaster 8000 Restoration

    Finally got some time to restart the project. Source display is restored (finally). Replacing the SMD LEDs requires a lot of patience. Ended up buying a cheap digital microscope and that really helped the process. I am not going to touch the other displays right now and come back to them at a later date.
    Posted to General Discussion & Questions (Forum) by dahiyas on Sat, Nov 21 2020
  • Re: Taking on the BM8000

    Sorry..I have been slowed down due to parts. I started on the updates to the display and ran out of LEDs (lost/damaged couple of them). Half-way through and waiting on LEDs now.
    Posted to The Workbench (Forum) by dahiyas on Mon, Nov 16 2020
  • Re: Taking on the BM8000

    I hope to replace the connectors this weekend. If everything works well, I will report back on the temperatures.
    Posted to The Workbench (Forum) by dahiyas on Tue, Nov 3 2020
Page 5 of 15 (142 items) « First ... < Previous 3 4 5 6 7 Next > ... Last » | More Search Options
Beoworld Security Certificate

SSL