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Old 07-03-2020, 04:11 PM   #41
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Default Re: Old Gateway 2000 speakers out of sorts.

BTW, what are the Voltages of the TA power amp IC pins?
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Old 07-03-2020, 04:21 PM   #42
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Default Re: Old Gateway 2000 speakers out of sorts.

Those are the two KIA324P's right? Do I need to test them with a signal playing like a youtube video or with just the speaker powered on?
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Old 07-03-2020, 04:23 PM   #43
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Default Re: Old Gateway 2000 speakers out of sorts.

No, the TA power amp IC mounted on the heatsink.
324's are just op-amps used in pre-amp sections..

Last edited by budm; 07-03-2020 at 04:33 PM..
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Old 07-03-2020, 04:23 PM   #44
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Default Re: Old Gateway 2000 speakers out of sorts.

Ok thanks, I tested looking at it from the back, testing from left to right, most didn't have but a little voltage, 7=7.6...8=14.6...12=14.73...14=14.57. I can list them all if needed.

Last edited by nomoresonys; 07-03-2020 at 04:39 PM..
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Old 07-03-2020, 05:25 PM   #45
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Default Re: Old Gateway 2000 speakers out of sorts.

Post #44: "7=7.6...8=14.6...12=14.73...14=14.57"
It looks like you may have counted the pins wrong due to the fact that pin 7, 14, and 15 are ground pins which you show Voltages there, please look at the spec sheet.
Please report all pins readings.
TA8248 pinout:
Pin 1: N.C.
Pin 2: Bootstrap 2
Pin 3: Output 2
Pin 4: VCC1
Pin 5: Output 1
Pin 6: Bootstrap 1
Pin 7: PWR-GND
Pin 8: VCC2
Pin 9: Ripple filter
Pin 10: NF1 (Negative Feedback 1)
Pin 11: Input 1
Pin 12: Input 2
Pin 13: NF2 (Negative Feedback 2)
Pin 14: Pre-Gnd 1
Pin 15: Pre-Gnd 2
Attached Images
File Type: jpg TA8248K pinout.jpg (71.5 KB, 9 views)

Last edited by budm; 07-03-2020 at 05:28 PM..
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Old 07-03-2020, 05:37 PM   #46
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Default Re: Old Gateway 2000 speakers out of sorts.

Ok, think I started at wrong end.
pin 2=14.57
pin 4=14.73
pin 8=14.6
pin 9=7.6
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Old 07-03-2020, 06:50 PM   #47
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Default Re: Old Gateway 2000 speakers out of sorts.

Please fill in these pins below so I can easily see what is going on, we are dealing with 2 amplifiers inside this IC:
Pin 1: N.C.
Pin 2: Bootstrap 2
Pin 3: Output 2
Pin 4: VCC1
Pin 5: Output 1
Pin 6: Bootstrap 1
Pin 7: PWR-GND
Pin 8: VCC2
Pin 9: Ripple filter
Pin 10: NF1 (Negative Feedback 1)
Pin 11: Input 1
Pin 12: Input 2
Pin 13: NF2 (Negative Feedback 2)
Pin 14: Pre-Gnd 1
Pin 15: Pre-Gnd 2
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Old 07-03-2020, 07:08 PM   #48
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Default Re: Old Gateway 2000 speakers out of sorts.

1: 0
2: 14.5
3: .5
4: 14.7
5: .5
6 .46
7: 0
8: 14.6
9: 7.6
10: .10
11: .47
12: .24
13: .01
14: 0
15: 0
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Old 07-03-2020, 07:14 PM   #49
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Default Re: Old Gateway 2000 speakers out of sorts.

Those are with just the main speaker and turned on, should I hook them both up and retest?
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Old 07-03-2020, 07:27 PM   #50
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Default Re: Old Gateway 2000 speakers out of sorts.

They do not look right. Notes: No need to have second speaker connected.
Pin 1: N.C. reported as: 0
Pin 2: Bootstrap 2 reported as:14.5. I need to check my speaker.
Pin 3: Output 2 reported as:0.5 this output pin should be at about 1/2 of the VCC.
Pin 4: VCC1 reported as:14.7
Pin 5: Output 1 reported as: 0.5 this output pin should be at about 1/2 of the VCC.
Pin 6: Bootstrap 1 reported as: 0.46. I need to check my speaker.
Pin 7: PWR-GND reported as: 0
Pin 8: VCC2 reported as:14.6
Pin 9: Ripple filter reported as: 7.6. I need to check my speaker.
Pin 10: NF1 (Negative Feedback 1) reported as: 0.10
Pin 11: Input 1 reported as: 0.47
Pin 12: Input 2 reported as: 0.12
Pin 13: NF2 (Negative Feedback 2) reported as: 0.10
Pin 14: Pre-Gnd 1 reported as: 0
Pin 15: Pre-Gnd 2 reported as: 0

Last edited by budm; 07-03-2020 at 07:28 PM..
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Old 07-03-2020, 07:50 PM   #51
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Default Re: Old Gateway 2000 speakers out of sorts.

TA8248, TA8229. Notes: (***V) = Voltage with headphone plugged in. When headphone is plugged in the VCC2 from the switched headphone jack is cutoff so there will no VCC2 on pin 8 of the TA chip.
Pin 1: N.C.
Pin 2: Bootstrap 2 =18.20V (0.56V)
Pin 3: Output 2 = 9.42V (0.51V)
Pin 4: VCC1 = 18.47V (18.47V)
Pin 5: Output 1 = 9.03V (1.00V)
Pin 6: Bootstrap 1 = 18.16V (0.52V)
Pin 7: PWR-GND
Pin 8: VCC2 = 18.47 (0.05V)
Pin 9: Ripple filter = 9.63V (0.51V)
Pin 10: NF1 (Negative Feedback 1) = 0.60V (0.95V)
Pin 11: Input 1 = 0.06V (0V)
Pin 12: Input 2 = 0.02V (0V)
Pin 13: NF2 (Negative Feedback 2) = 0.60V (0.56V)
Pin 14: Pre-Gnd 1
Pin 15: Pre-Gnd 2

Last edited by budm; 07-03-2020 at 08:24 PM..
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Old 07-03-2020, 07:56 PM   #52
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Default Re: Old Gateway 2000 speakers out of sorts.

Ok, looks like both output and one bootstrap is way to low.
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Old 07-03-2020, 08:19 PM   #53
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Default Re: Old Gateway 2000 speakers out of sorts.

Per your readings in post #48
Pin 2: Bootstrap 2 reported as:14.5
Pin 6: Bootstrap 1 reported as: 0.46. This one looks bad. You may want to check that cap between pin 5 and pin 6.

Pin 3: Output 2 reported as:0.5
Pin 5: Output 1 reported as: 0.5
I expect them to be like that, 0.50V, if pin 8 VCC 2 Voltage is not present when headphone is plugged in, but you have VCC2 on pin 8 of the IC.
I guess you can try new TA chip.

Last edited by budm; 07-03-2020 at 08:24 PM..
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Old 07-03-2020, 08:41 PM   #54
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Default Re: Old Gateway 2000 speakers out of sorts.

I think that cap is the green one, I did the voltage test without headphones plugged in.
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Old 07-03-2020, 08:52 PM   #55
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Default Re: Old Gateway 2000 speakers out of sorts.

I bet it is that TA, because it's the hardest part to replace on the whole board, that's my luck.
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Old 07-04-2020, 05:49 AM   #56
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Default Re: Old Gateway 2000 speakers out of sorts.

Can you tell which green ceramic cap relates to bootstrap one, is it the one closest to the TA chip? tried measuring the voltage, if I hit the right solder joints I didn't get much voltage from either one??
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Old 07-04-2020, 01:48 PM   #57
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Default Re: Old Gateway 2000 speakers out of sorts.

The bootstrap cap will be electrolytic cap, look at my post 45 to see how the cap is connected to the bootstrap pin and the output pin.
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Old 07-04-2020, 03:25 PM   #58
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Default Re: Old Gateway 2000 speakers out of sorts.

I can't tell it kind of looks like it traces back to the one I changed or is it c25 or c26? I can't tell from the scemo.
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Old 07-04-2020, 03:40 PM   #59
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Default Re: Old Gateway 2000 speakers out of sorts.

Check the resistance between the bootstrap pin and the output pin of each amplifier to see what they show.
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Old 07-04-2020, 04:18 PM   #60
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Default Re: Old Gateway 2000 speakers out of sorts.

Pin 2: Bootstrap 2 resistance between 2 and 3 is 219 meter set at 2000 ohms
Pin 3: Output 2
Pin 5: Output 1 resistance between 5 and 6 is 546 meter set at 2000 ohms
Pin 6: Bootstrap 1
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