Viasho 1W 532 PSU question?

[norty303]

Was the venue hot?

In the last few weeks of hot weather, me and another forum member have had green modules (not Viasho) whither away to nothing during the night, usually causing the driver to failsafe ultimately.

[greenalien]

Was the venue hot?

Given that Saturday night was the hottest so far this year, and the venue had no aircon, it's not surprising that it was pretty hot - like a sauna! However, the Viasho module has been giving indications of fading away for a while now. I'll report more in a couple of days when I've had a chance to get the module out of the projector.

[greenalien]

OK, I now have the laser head and PSU on my bench. I fired it up in TTL mode, and it looked good for a few minutes, then the brightness slowly reduced so that it was down to about 10% of maximum after about 15 minutes. This is exactly what it was doing in the projector under analogue modulation, so there's definitely a fault.
I'll send Frank a PM and see what sort of response I get, and will report back here.

[Pitts]

Hi guys,

This may not be applicable here in this case but it is absolutely imperative that the terminal strip screws are down tight and that the bare wires are correctly in the holes before doing same.

I have two Viasho 1.7W that work well (now).

However I had all sorts of weird issues due these useless terminal strips and what's more they work loose over time.
Viasho also have made a very untidy job of the wiring into these by soldering several wires at the point of insertion. This being the case it is very easy for these to not be properly connected leading to who knows what issues dependent on which wires are touching.
I experienced cutting on and off, pulsing and power issues all due to this green screw type connector.
It could mean that the TEC or something else is not getting what it needs.

The picture in this thread shows the terminals well.

Just FYI

Regards

Ray
NZ
Just FYI

[greenalien]

Thanks for the pointer, I'll check the terminal strip tightness. I'm now in correspondence with Frank and am waiting to see what his engineer suggests. He requested a detailed photo of the PSU, and current and RT1 readings from the front panel meter. Current values don't change, and RT1 stays steady at -40.3.

Update - 3rd May - just had an email from Frank - his engineer suggests that one of the PSU quad op-amp chips has failed, so I'm going to have a go at replacing it myself. So far, I have succesfully removed the old chip, and am awaiting delivery of a replacement from Farnell.

[greenalien]

I'm pleased to report that changing the chip has fixed the problem, and the laser has now been running continuously for over an hour without any noticable drop in power. Please see this photo that Frank sent to me, identifying which chip had been identified by his engineer as having failed.


This was my first attempt at replacing a SMD chip, a bit fiddly but it seems to have worked out OK.

Thanks to Pitts for the advice about checking the terminal strip tightness - although that wasn't the cause of my problem, when I checked I found that half a dozen of the screws were significantly loose, so this may have saved a future failure.

More testing this evening, if all is still OK then I'll reassemble my projector tomorrow. Thanks to Frank and his engineer for splendid customer service, much better and quicker than having to pack everything up and ship it back to China!

[Robin]

I'm looking for some info on the smaller Viasho OEM drivers. I have a 1 watt unit that is putting out plenty of power, but appears to be running TEM-01. Frank advised me to adjust the W5 pot on the driver as a troubleshooting step but did not indicate what that pot adjusts, or what range to keep my adjustments in. Call me crazy, but when working on lasers, I prefer making adjustments I can measure.

Any tips?

[shrad]

Hi everyone

Sorry to resurrect an old thread like I do, but I have a nearly identical problem on a viasho 1W head like this one

I have had them with low power output and I'm in the route to realign them

I have measured diode current which is nice and not overdriven, but there seem not to be any output on the TEC

I measured 0V at the TEC leads and no current on the TEC, and RT1 reads -24 as well as RT2

Would that be the same problem?

Those heads were sitting on subwoofers from what I was told by their previous owner, and everything would be misaligned, so maybe there is also a problem with trimmers inside... I don't know what they do apart the markings on the board, but if someone had a clue on what sets what, that would be wonderful

So if Frank is around here or anyone else who knows the whereabouts, please tell me if you can provide any information!

[Bradfo69]

I now own the Viasho that started this thread as I bought it from Jim (smog) a couple years ago. It's been running around 400mw since I got it only because Rob replaced the pump diode and didn't have enough time to get it completely aligned before Jim shipped it to me. It's had maybe 8-10 hours since then and was last used at SELEM last August (still had incredible colors and several people commented how nice the output looked). I pulled it out last weekend and the green is now extremely faint. I talked with Rob a few months back and will be shipping it to him at some point when I have time to extract it from the projector but, it sounds like these Viasho's have been less than stellar. I'm just wondering if I should replace it all together with a different 1 watt green. Or maybe 1/2 watt since restoring it to a full watt may affect the wonderful hues this projector makes.

Edit: Just an FYI - top shelf left hand side is the projector in question. http://www.youtube.com/watch?v=lZYtZ_GQY_E

This one really shows it well - the top shelf on the left and the top shelf on the far right are two of mine. Both "should" be about equal but the yellows, oranges and blues seem more "vibrant" on smogs. http://www.youtube.com/watch?v=oDj0N6J5tVk

[shrad]

thanks for the input

it seems they are sensitive to vibrations, and sadly their environment is usually loud music, so they disalign

I wonder if once realigned it would be possible to epoxy the mounts so they don't fall apart as a fly fart

I realigned mine briefly with bare hands and only a sheet of paper to get a clue about brightness, and it seems to do more than 400mW out of the 30mW it did when I got it

the sad thing is they have no FAC on the pump diode, and I'm considering getting a cylinder lens on the beampath