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CHAUVET RH1 HYBRID LAMP ISSUE


partyanimallighting

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Hi all, I'm just wondering if anyone is familiar with the Chauvet RH1 Hybrid unit and any lamp issues they may have with them. I've got one that strikes on startup and then the lamp douses after a few seconds. I tried swapping out the 60MM lamp fans, the main 92MM lamp fan, lamp and ballast with those from a known working unit with no success. I previously had issues with this unit with a faulty 60MM lamp fan that was causing the same issue but I've replaced all the fans and the problem has not been resolved. Any feedback will be greatly appreciated.

partyanimallighting

 

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It seems that the fixture thinks it's overheating. The fan douses after a few seconds on an initial cold startup so it's definitely not an overheating issue. There are two 60MM sensor fans to either side of the front of the head labelled "lamp fan" and these are twitching on initial startup but not spinning. So I suppose that's sending a signal to the unit to douse the lamp when it strikes. BTW, these fans are working fine in the functional unit.
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You have already ruled out the lamp itself (and ballast etc.) but haven't mentioned test of any temp sensor themselves. I don't know the RH1 but have worked a lot on the R2 Beam which uses the (frankly awful and expensive) Sirius 230w lamp and those fixtures have a lot of temperature needs and heat issues. These include crispy wiring that can lead to unstable lamp on situations. Without one in front of me, I can't recall the exact position of the lamp temp sensor but it's not in an unusual place.

 

As you say, if it's not actually hot but is dowsing the lamp then I'd look at the sensor circuit. But perhaps don't rule out an intermittent connection to the lamp which means the lamp doesn't stay on and then the fans etc. follow suit. I recently had another manufacturer's fixture with reported lamp dowsing issues that turned out to be nothing more complex than a broken and arcing supply conductor.

 

I wouldn't expect the control board to take many cues from what the fans are doing, they often just respond to the control so any odd behaviour is usually found to be caused in the feedback circuits or the control itself. Hunting through any diagnostic menus might prove useful such as reported temperature etc (Sys Info). Not sure if these models report fan speed to the user, it's usually only on higher end fixtures.

Edited by indyld
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Hi indyld, the temp sensor is inside the lamp housing and I already tested it for continuity and then bypassed it too with the same result. As for the issues with temperature and heat issues, if one fan goes down, the unit will quit on you for sure. I think I narrowed down the problem anyway. It seems to be the MH078E driver board, which controls focus, zoom etc along with the lamp fans located in the front of the unit. I tested working and non-working units side by side and realized that there was no focus or zoom function, which is controlled by this pcb, along with the two fans. Output on the functioning unit at the lamp terminals was around 11VDC but on the faulty unit, only 3.5VDC, hence the fans not spinning. So it's a voltage issue on this pcb that's causing the issue. And yes, just to confirm, I swapped the pcb's around and the lamp issue followed it into the working unit and the problematic unit functioned perfectly. So now I have to try to find the faulty component on the pcb, check for availability, replace it and see what happens.rolleyes.gif Edited by partyanimallighting
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The PTH2020302234881 board is costly enough at $130 to make hunting a fault attractive. It sometimes can be a shorted semi or cap if not a really obviously physical PCB issue like dirt. I'd check that the main chips are getting the correct voltage when live. Then dead testing with known-good board and diode test is your friend, a few comparative diode tests to ground at different points may soon confirm (if there is nothing obvious by eye like bits that have blown up).

 

If you don't have any control from that board motor controls then it sounds like a voltage issue on the board itself that can be caused by a short or sometimes non-functioning local PSU elements. A squint at a blurry photo of the board it seems to house circuits of motor controllers in 3 sections on that side plus some fan switching at one end and control brain at the other. There looks like there might be some components that create a voltage for the board or the fans so I'd start there.

 

If it's just a stock SMD component, then happy days. If the complex bits of the board like a controller chip is goosed then not so much.

 

My biggest problem with SMD stuff is being able to find out the spec of a replacement and this is where donor boards make life easier.

Edited by indyld
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Hi Jivemaster, they're pristine inside and out. Indyld, at $130.00, plus shipping to my Skybox, plus overseas shipping, handling, duties and taxes, makes hunting for the fault is the best option I have right now. The pcb is simple enough, 28VDC in, with a (unknown) numbered voltage regulator, a few caps, what seems to be a voltage filter and a u/p. To the rear of the pcb are 5 DRV8841 stepper motor drivers. I've tested both pcb's live and I'm getting 28VDC in and 12VDC out on both regulators but 3.5VDC on the fan terminals on the faulty one and no functions on the stepper motors. Hopefully, I can find the problem (with your assistance PLEASE!! unsure.gif) BTW, is there an option to upload images to my posts? I am only getting options to post images via links.

 

Let's try a simple copy and paste.

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No. You cannot upload images directly to the forum. This is so that the server and hosting costs remain reasonable.

 

Just upload to an online host - tinypic.com / imgur.com etc and paste the [ IMG ] link into your post

 

Or host on your own website and copy the link? (By the way; that’s quite some website! ;)

Edited by david.elsbury
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Photos can only be posted via 3rd party hosts. Some higher res pics would be useful as it looks like there is a quad flat package controller on the opposite end to what I assume is the fan outputs and if there is nothing activating the motor drivers either, you gotta wonder if the control side is actually doing its thing or even getting the Vcc it needs (3.3v or whatever). On the awful picture I have, it's not clear if there is a component there or not. There is also something under a QC sticker in the middle with a crystal next to it.

 

I'm not quite clear if none of the 2 attributes on each of those 5 stepper drivers are working or just some of them but obviously if only some then this gives a particular part of the board to investigate further. If all, then the controller side is under more suspicion if on the same board. I assume that it seems that the same driver chip circuit type is also being used to control the fan speeds, along with the focus/zoom etc. or does it appear that the fans are switched/controlled by a simpler circuit? If the former, then do the zoom chip and the fans chips share a bulk capacitor, for example?

 

It wouldn't hurt to get the known-good board side by side with the faulty one and do a diode mode test between ground and various things such as the pins on the fan connectors, semi-conductor pins, capacitors +ve side etc. Red probe on the ground plane, black on any terminal you wish to compare, then look for significant differences in readings between the boards. You can use the ohmmeter but diode test readings usually are more user friendly and stabilise faster. This is can be a quick way to find where to start looking for shorted junctions etc.

Edited by indyld
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Hi indyld, I'll send some links to some pix via a 3rd party fileshare in a bit. I'm hoping it's something simple like the regulator but I cannot find the component number anyway and it makes no sense to swap out the regulator from the working board. That's just plain idiotic to go screw around with the working board.

 

Here you go. I included some pix of the regulator that I can't confirm.

 

https://imgur.com/jwgqmV7

https://imgur.com/q1vrehv

https://imgur.com/zPiUapX

https://imgur.com/hr3ShUl

https://imgur.com/acZ4E7a

 

 

TD7591SADJ

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It takes a bit of messing about with a continuity checker to try to reverse-engineer these kinds of boards but my guess from afar is that the large regulator creates a voltage from the 28v in and then this possibly feeds the LM117 3v3? If other stepper drivers on the board work (e.g the controller is powered and working) then one might assume that both those regs are OK but it's worth testing them. For testing, I would take a punt on the pinout of the 7590. There is also something on the flip side of the other fan output that might be of interest.

 

It's kinda hard to tell but it looks like the fan outputs possibly aren't driven by one of the DRV8841 channels but, as mentioned before, it is a good plan to find some commonality between the fans and other non-working steppers.

Edited by indyld
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OK guys. New update. I tested each board installed in their respective units and the dousing of the lamp is definitely caused by the failure of the defective board to power up ONE of the lamp fans. I then checked the voltages on the majority of the components and the majority of voltages are consistent, with the exception of one component (not sure what type it is). On the functional board the voltages are 12VDC and 1.5VDC and the other (faulty) board it's 12VDC and 8VDC. Could this be the culprit? All the other voltages are equal. It's bottom right hand in the linked picture.

https://imgur.com/a/jKqJHOk

 

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The black block is a diode of some kind, often switching or Zener and that part of the board switches "something". A few beeps with the fan terminals to around that area will tell you if this is the bit that switches the fans. There are two transistor-y looking things that I wondered about when I first saw the blurry image of the board simply because there are two of them and it seemed like there were two fan outputs in the original post.

 

Like all semiconductors, any of those components can fail short.

Edited by indyld
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