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electrodoc

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About electrodoc

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  1. Hi, I Have 10 Thompson Flyback Transformers for sale HR Part No= HR 8317
  2. HI, i have Hundreds of Television coin meters Clockwork @
  3. Yes a picture of both sides of the board if possible if you could put a sticker on one corner going from the solder side to the component side may help with orientation of the components.
  4. [glow=red,2,300]***__-- TUBE BASE VOLTAGES CAN AND WILL!! BITE--__***[/glow] I'm not familiar with this model but providing the chip that you refer to isn't fastened to a heatsink then this procedure is a failsafe way of finding where the fault is. It can be used on any transistor driven gun array and i always employ this method. First check the drive circuit on the tube base, there will be a plug going from the tube base to the main board where the IC001 lives. three of these leads should be traceable to the red,green and blue drive transistor base connections. disconnect / cut the wires for the red and blue and swap them over. Then if your screen still lacks red there is a fault on the tube panel or possibly the tube itself, if your screen lacks blue then the fault lies within the RGB driver chip on the main board. Reconnect your swapped leads and then check the tube by following the track from the 'BLUE' drive transistor to the relevant pin on the tube base socket and desolder the pin, do this with the 'RED' pin also. Then with a thin piece of insulated wire soldered to the 'BLUE' tube base boards socket pad* (see picture) touch the other end of the wire to the tube sockets 'RED' pin.
  5. what is the exact problem with it?
  6. The filter is working very well now since changing C1, C2 and C3's values to those you specified ,thanx guru. However the frequency response is very dependant on the setting of RV1 and the intensity of the audio signal, with OR without the 3.3nf cap. The unit will be used in a very loud room and music volumes will be lower in some parts of the room and higher in others. So this problem is an issue which would need resolving. Changing the microphone type or adding desctrete extra stages isn't a problem for me, one i was toying with is the addition of the filter circuit here.
  7. http://www.electronics-lab.com/forum/index.php?board=15;action=display;threadid=794
  8. When using a transistor as a buffer/inverter I find a simple way of remembering the rules for these jobs are as follows.. To remember the transistor type when looking at schemetics I use Point iN Please and Not Point iN, these are for the emitter arrow directions and the voltage polaritys for them to work. For the polaritys i use the emitter as my reference and proceed by using each junctions P or N initial as the (P)ositive or (N)egative supply they need to get to switch through between Emitter and Collector. therefore a PNP to switch needs a positive current or feed to the emitter and a negative (Lower current) feed on the base for the collector to be positive. Hope this helps.
  9. http://www.designnotes.com/CIRCUITS/ledflash.htm this does 10 leds left to right to get a fading effect simply modify the led driver like this link shows.
  10. Hopefully this new theory thread will help in my own and other users quest's to understand How these filters are worked out.. A few questions to sart the ball rolling would be... 1)..I can see that R2 + the volume control (RV2) sets the gain for the primary amplifier but what about R3 and R6, is R3 for stability and are R6 and R7 needed? 2)..How do I work out the gain that I want and then work out the resistances required? 3)..Is the gain affected by any bandpass filters and vice versa?
  11. thanks for that audioguru, but i do know about the frequencies of audio structures, i'm just not that good at filter theory. would you mind explaining the theory behind my filter? I'll start a new thread in the theory forum. Here's the follow on link.. www.electronics-lab.com/forum/index.php?board=15;action=display;threadid=793&start=0
  12. Hi all, this is a forum linked from another thread i started for a Low Pass Filter which would give a visual display of the Bass beat from a disco system. Here's the link to that... www.electronics-lab.com/forum/index.php?board=13;action=display;threadid=332
  13. ??? Thanks audio guru. I used a 22nf + a 2.2nf for the 18nf and the 3.3nf respectively ( numbers on caps where 223 (22nf) and 222 (2.2nf). If these capacitor code translations are wrong then please mention it. shurely these values should be ok? but it wouldnt play ball. The 2.2nf was tried between the current limited power output of R8 and T1 collector. also tried between the wiper of RV1 and T1's collector and between the wiper upto R8'S output. But to no avail. It would flash to the beat of the music but also flash to any other noise (ie talking in the room). Please help. thanks,, Rich
  14. I require a led to flash to the Bass Beat of music using a microphone as a pickup source, hopefully using the PMK103 circuit outlined above.
  15. would this just be a visual display of the game or do you want the game to know when you have connected four?
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