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Search: Posts Made By: Khron
Forum: Audio Equipment Discussion 07-11-2018, 04:01 AM
Replies: 27
Views: 4,377
Posted By Khron
Re: MOTU 896 mk3 re-cap

http://uzzors2k.4hv.org/projectfiles/auxsmps/UC3842%20Flyback%20Converter.GIF

Except the controller and the MOSFET are an "all in one" device. I see that's not visible in the photos i've attached...
Forum: Audio Equipment Discussion 04-17-2018, 10:51 AM
Replies: 24
Views: 3,738
Posted By Khron
Re: Replaced Caps in Emu 1820 but No POWER

https://fthmb.tqn.com/8hz6SqMMszBm_pUWVjsZrpWGWiU=/768x0/filters:no_upscale():max_bytes(150000):strip_icc()/enable-device-windows-5989d5c8396e5a0011547d85.PNG
Forum: Audio Equipment Discussion 03-18-2018, 11:04 AM
Replies: 16
Views: 757
Posted By Khron
Re: LG home theater no power

I can't be 100% sure from the first photo, but it kinda looks like most of the components between the PWM chip and the MOSFET gate are toast.
...
Forum: Audio Equipment Discussion 02-27-2018, 02:49 AM
Replies: 50
Views: 1,106
Posted By Khron
Re: Help with Onkyo TX NR 838

What i'm seeing in the service manual is two 100 ohm resistors, not 100Kohm.

Did you mis-type that, or did you really use two 100K's in your cable?

PS: Can't really see the point in adding...
Forum: Audio Equipment Discussion 02-25-2018, 02:20 PM
Replies: 24
Views: 700
Posted By Khron
Forum: Audio Equipment Discussion 02-25-2018, 11:43 AM
Replies: 24
Views: 700
Posted By Khron
Re: Av123 MFW-15 power supply problem

No, that's just to make sure the power supply board and the transformer both work as intended. And yes, for the probing.
Forum: Audio Equipment Discussion 02-25-2018, 02:45 AM
Replies: 24
Views: 700
Posted By Khron
Re: Av123 MFW-15 power supply problem

The MOSFETs are actually IRFB31N20D, the 807 is just some date-code thing, see page 8 of the datasheet:

https://www.infineon.com/dgdl/irfs31n20d.pdf?fileId=5546d462533600a40153563661a62157

To...
Forum: Audio Equipment Discussion 02-24-2018, 11:05 AM
Replies: 3
Views: 225
Posted By Khron
Re: After a good DAC

I'd vote for a small 2-channel USB interface you can find for cheap enough on the used market. Something along the lines of a Focusrite Scarlett 2i2, or some older units from M-Audio.

PS:...
Forum: Audio Equipment Discussion 02-24-2018, 04:43 AM
Replies: 24
Views: 700
Posted By Khron
Re: Av123 MFW-15 power supply problem

<Nevermind, i mis-read some things>
Forum: Audio Equipment Discussion 02-23-2018, 06:19 AM
Replies: 2
Views: 132
Posted By Khron
Re: FBT Mitus Active Stage Monitor 210 MA

"FB" would indicate, to me, rather a ferrite bead.

Can you trace, at least vaguely, where that trace goes, and/or where that comes from?

Photos of the board(s) would help, too.

<edit>
...
Forum: Troubleshooting TVs and Video Sources 02-12-2018, 02:11 PM
Replies: 8
Views: 214
Posted By Khron
Re: LG 32LB561 (32LB561U) very dim backlight

So then, it's definitely the backlight itself, that's at fault?
Forum: Troubleshooting TVs and Video Sources 02-07-2018, 03:39 PM
Replies: 8
Views: 214
Posted By Khron
Re: LG 32LB561 (32LB561U) very dim backlight

In that case, math says i should see anything between 1.3-1.8v (those six sense resistors end up being about 0.22ohm in total). Except that that's not really happening.

I soldered back that series...
Forum: Troubleshooting TVs and Video Sources 02-07-2018, 10:51 AM
Replies: 8
Views: 214
Posted By Khron
Re: LG 32LB561 (32LB561U) very dim backlight

The current-sensing resistor is actually a group of four 1ohm resistors, one 2ohm and one 8.2ohm, all in parallel.

I've probed the lower of the two wire-jumpers between the backlight connector...
Forum: Troubleshooting TVs and Video Sources 02-07-2018, 10:39 AM
Replies: 8
Views: 214
Posted By Khron
Re: LG 32LB561 (32LB561U) very dim backlight

Exactly - no reaction when changing the "backlight" setting in the picture menu, and it didn't get any brighter with the PWM pulled to 3.3v.

I re-probed (with PWM still hardwired to 3.3v), and i'm...
Forum: Troubleshooting TVs and Video Sources 02-07-2018, 10:22 AM
Replies: 8
Views: 214
Posted By Khron
LG 32LB561 (32LB561U) very dim backlight

Right, so a client brought in this 32" LG TV a couple days ago, with the symptom of the picture being very dim, and allegedly dimming even further within 5-10mins.

What i've tested and/or...
Forum: Audio Equipment Discussion 01-01-2018, 10:06 AM
Replies: 273
Views: 71,306
Posted By Khron
Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Amp chip's blown? Sounds like either oscillation, or a considerable DC offset's going on...
Forum: Audio Equipment Discussion 12-24-2017, 04:20 AM
Replies: 11
Views: 494
Posted By Khron
Re: Novation SuperNova 2 Rack - Freezes up.

That's pretty great!

I've had a similarly positive experience with Focusrite's own tech-support in the UK. A year or two back i had bought a faulty Scarlett 18i8 (USB socket was destroyed), which...
Forum: Audio Equipment Discussion 12-21-2017, 09:53 AM
Replies: 13
Views: 615
Posted By Khron
Re: Onkyo tx sr 607 -New DSP chip installed

I can't be sure, but i wouldn't be surprised. Either way, i'm pretty sure (detailed) datasheets can't be found for those custom(?) chips.

That being said, if it has a flash chip nearby, that could...
Forum: Audio Equipment Discussion 12-21-2017, 06:01 AM
Replies: 13
Views: 615
Posted By Khron
Re: Onkyo tx sr 607 -New DSP chip installed

I wonder if the DSP chip might have some internal EEPRROM / flash memory, where it has (or should have) some ID and/or configuration data programmed...
Forum: Audio Equipment Discussion 12-14-2017, 06:27 AM
Replies: 27
Views: 4,377
Posted By Khron
Re: MOTU 896 mk3 re-cap

I'm willing to bet good money you can't get any such detailed information from... anywhere, really. Not from the internet, and deffo not from MOTU themselves.

One first step you can take is to...
Forum: Audio Equipment Discussion 11-28-2017, 05:29 AM
Replies: 273
Views: 71,306
Posted By Khron
Re: Repairing Alesis M1 Active mk2 Monitor Speakers

As a rule of thumb, if an electrolytic says "VENT" on it, i don't trust it as far as i can throw it. Only (some of) the crap brands have that written on them; the good ones don't - coincidence? :D
...
Forum: Audio Equipment Discussion 11-26-2017, 12:51 PM
Replies: 273
Views: 71,306
Posted By Khron
Re: Repairing Alesis M1 Active mk2 Monitor Speakers

1) Photos
2) Tested C8 / C35 how, exactly? And "they seem fine" to you, based on what?
3) What colour code / resistance can you measure on R28? They should be the same (at least in theory).
Forum: Audio Equipment Discussion 11-25-2017, 07:10 AM
Replies: 273
Views: 71,306
Posted By Khron
Re: Repairing Alesis M1 Active mk2 Monitor Speakers

That's what i had tried to confirm mitigate by having said:
Forum: Audio Equipment Discussion 11-23-2017, 03:12 PM
Replies: 273
Views: 71,306
Posted By Khron
Re: Repairing Alesis M1 Active mk2 Monitor Speakers

On a good MOSFET, you'd only expect around a diode-drop with the red probe on the source, and the black probe on the drain. So if you're getting 0.57v both ways between the drain and source, that's...
Forum: Audio Equipment Discussion 11-23-2017, 09:48 AM
Replies: 273
Views: 71,306
Posted By Khron
Re: Repairing Alesis M1 Active mk2 Monitor Speakers

Touch the gate and source of Q1 together (to discharge the gate) and measure again. If there's any charge left on the gate, that will keep the MOSFET open, and the drain-to-source voltage drop will...
Showing results 1 to 25 of 500

 
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