Mulja tv repair portal
Equipment Repairs => DVD/VIDEO/Home Cinemas/Hi-Fi/Mp3/Camcorder => Topic started by: djkrasikn on November 22, 2022,14:20:59
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hello
I sent to service and they fixed the display but the vcr couldn't fix it. After a thorough examination I was able to understand that the vcr mechanism is driven by ic2501 /BD6904FP/. On BD6904FP spec leg 1/21 - 12v measured 12.6v, leg 7 - 17v measured 16v and leg 19 - 5v here comes the problem measured 0.1v. This pin 19 comes from ic6302. on ic6302 at the input (4) 5.8v and at the output (1) 0.1v comes out. where does the problem come from?
i have the schematics i can send them
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IC 6302 is merely a switch for the 5V supply to IC 2501. The switching voltage comes from pin 75 of IC6001, the system control/servo/timer IC. You need to determine if the switching voltage is present, if IC6302 is operational or if the output of IC6302 is shorted to ground. Bruce
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thanks
I will check now
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I just checked IC6302 pin 1/output/ is not on ground
at the input of IC6302 pin 4 there is 5.8 volts
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What about the switching voltage that is supplied by IC6001 to turn it on. There'll be no output without that.
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Hi, what should I do?
I made videos
https://www.youtube.com/watch?v=hZwikma_E_U
https://www.youtube.com/watch?v=Q6478jU54vA
this model how it is made, only i have no error on the display
https://www.youtube.com/watch?v=yZhVsh4zBkA
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What happens if you short IC6302 input (5.8V) to its output? Does the VCR function then? The videos tell me little that's useful.
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From the picture IC6302 pin 3 /on/ should turn it on, but I don't know where to look for it.
The ones in the picture refer to IC3002; QR4501; IC3906; IC7402 I measured the voltages when assembled and switched on
IC3002 pin 1 measured input 1.68 volts, pin 5 output 0.03 volts per case
IC3906 pin 1 measured input 5 volts, pin 5 output 4.7 volts per case
IC7402 pin 1 measured input 0.17 volts, pin 5 output 0.03 volts per case
QR4501 in one place is 12 and in the other two 0 per case
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IC7402
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IC3002 + IC3906: Input pin is 8 = 5.8V, Output pin is 1 = 5V, On/Off Switching pin is 5 = high . This is the same in all modes i.e Play, Stop, Rec.
IC3906: Input pin is 4 =5.8V, Output pin is 1 = 5V, On/Off is pin 3 = 4.6V in all modes.
QR4501 has 4.6V on the base only in all modes.
The service manual does have a voltage chart for all ICs .
I suspect it all comes back to Micro IC6001 not supplying switch-on volts from pin 75 to IC6302. I wouldn't attempt to remove the micro but with an injection of soldering flux under it and judicious application of a heat gun to the top of the IC you might get sufficient solder flow at the ball joints to remake any poor contact.
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I removed the chip but I can't find such an IC 6001 M37761vlve-1
I don't know where to buy
this one is similar but it won't happen for sure
https://www.aliexpress.com/item/1005002778857085.html?gatewayAdapt=4itemAdapt
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Well, at least we livened up the forum for a while.
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I will order the part and when I replace it I will write. Happy Holidays!