I love modern technology

Relax in southern comfort on the east bank of the Mississippi. You're just around the corner from Beale Street and Sun Records. Watch the ducks, throw back a few and tell us what's on your mind.
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terkio
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Re: I love modern technology

Post by terkio »

It is the can with about no lead on each side.
On top of this, it is crowded around.

I do not have an airgun.
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JR.
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Re: I love modern technology

Post by JR. »

If you can reach the solder pad at all with an iron tip you should be able to melt it, maybe put some fresh solder on the tip.

I reworked SMT with an old school iron for years before upgrading to hot air... hot air is better/easier.

JR
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terkio
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Re: I love modern technology

Post by terkio »

I'll try heating. There is very little accessible to touch with the iron tip and no way to heat both side simultaneously.
I think of destroying the case to have access from the inside. Pliers, cutter, whatever ?
Is there a chance, this way ?
I have seen a video, where the guy yanks SMC caps with pliers in a twisting move, but it is not clear wether the PCB pads survived.
I am 99% sure, all this monitor needs is this one cap renewed.
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AnalogJoe
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Re: I love modern technology

Post by AnalogJoe »

terkio wrote: Fri Jul 10, 2020 7:07 pm
I have seen a video, where the guy yanks SMC caps with pliers in a twisting move, but it is not clear wether the PCB pads survived.
I am 99% sure, all this monitor needs is this one cap renewed.
Are you refering to Mr. Carlson's Lab videos? He yanks the caps with some pliers. I remember I cringed when I saw that, I guess it depends on the PCB but its a gamble, I've lifted PCB tracks for a lot less than that.
Bonum certamen certavi, cursum consumavi, fidem servavi.
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terkio
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Re: I love modern technology

Post by terkio »

May be this guy....
Indeed, it looks like BS because there is absolutely no information about wether the board was actually good to complete the work.
So, I will not try this gamble.

Do you think there is a chance, carefully destroying the cap to get access at the pads ?
Well, I know what I could do: Find a junk board with such caps and try this operation.
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JR.
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Re: I love modern technology

Post by JR. »

terkio wrote: Fri Jul 10, 2020 7:07 pm I'll try heating. There is very little accessible to touch with the iron tip and no way to heat both side simultaneously.
you don't have to heat both sides at the same time... you can unsolder one side and tilt the cap up, the unsolder the other side.

I think of destroying the case to have access from the inside. Pliers, cutter, whatever ?
I have done that with small electrolytic caps.
Is there a chance, this way ?
I have seen a video, where the guy yanks SMC caps with pliers in a twisting move, but it is not clear wether the PCB pads survived.
I am 99% sure, all this monitor needs is this one cap renewed.
If there are vias in the pads that may survive a hard yank, but far safer to use heat.

JR
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JR.
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Re: I love modern technology

Post by JR. »

My drama sourcing cost effective 5.1 (actually 6 channel) surround decoding, that works reliably is ongoing.

I have exhausted myself trying to find an A/V preamp only that isn't multiple $k audiophoolish...

Just found a new different cheapo ($32) that checks all my boxes, so fingers crossed.

I have even been looking at cheap AV receivers but with the feature set I want they have 80-150W amplifiers inside. I suspect amplifiers these days are pretty cheap.

JR
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JR.
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Re: I love modern technology

Post by JR. »

I don't want to jinx it by talking about it but surround sound decoder seems to be behaving better for now.

I corrected one malfunction that seems like operator error... There was a built in leveling function that caused the noise floor to bloom up during dramatic pauses. I think I experienced this with the previous monitor so who knows.. :roll: the DSP definitely seems local to the TV monitor. Stopped happening with TV monitor settings set to normal theater mode.

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JR.
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three steps forward two steps back..

Post by JR. »

The new improved (still cheap $32) surround decoder arrived. It took me almost a day going back and forth with a patient customer service tech to get it working as well as it will.

It turns out there was a Dolby audio setting in the direct TV receiver that needed to be set on... "and" The ROKU environment needed to be set for dolby surround DTS. So finally getting 5.1 dolby surround all the time (so far).

1-The first step backwards is a low level hum-buzz, in all channels. Not audible during program, but audible during quiet parts.

2-The second step backwards is inability to drive my amps to full output. This is not a new problem the previous cheap decoders didn't either.

It turns out my Hypex amp modules want to see 2.5V for full power and the decoder is only rated for 1V. This is not unexpected for DAC running from 5V supply.

My Hypex amp modules are discontinued but apparently they made a version of my model with an onboard gain stage buffer. Apparently I am not the only one with this problem.

I miss the meters I had before with the stand alone amps. I figure one LM339 per channel will give me adequate blinky lights.

The hypex amps have adequate +/- rails but as far as I can tell they don't encourage grabbing power from there, tweaking the amps to have more gain is somewhat thwarted by no published schematic as far as I can tell (I should ask Bruno, as if he remembers me, but if it was that easy they would have done that instead of adding a buffer model.) :lol: . Hypex has a high current 5V rail available so I can use that to power the surround decoder eliminating one wall wart.

Since I only need less than 10 dB more gain I am leaning toward active differential that will give me +6dB without heavy lifting. To deal with the low level hum/buzz I am thinking about differential between decoder to bump stage, and differential with dual active output lines.

I don't want to go for exotic op amps but expect I can get it done with repurposing an additional 5V wall wart to provide +/- 5V... 2.5V audio is only 1.25V on both + and - legs which is pretty much possible with single 5V rail, should be easy peasy with +/-5V.

JR
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mediatechnology
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I love old technology

Post by mediatechnology »

I figure one LM339 per channel will give me adequate blinky lights.
I'm shocked, just shocked JR.
Welcome back from the dark side. :D
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