Smoking Jobo ATL-2300

[Tom Kershaw]

About 20 minutes ago, as my Jobo machine was running an E6 process without film to clean the system through, the Jobo stopped dead, i.e. it cut its power supply off and smoke started bellowing (in fairly dramatic quantities) from the central control area. Removing the front and rear covers does not reveal anything out of the ordinary, but there is a distinctive burnt smell emanating from the section between the three front circuit boards and the vents; so perhaps the fan has "blown up".

Any others with experiences of a smoking Jobo?

Tom.

 

[MikeSeb]

Yes, with a Jobo ATL-1000. You may need to reset a circuit breaker (instructions or Jobo support should be able to tell you where it is. But you may have fried something, as was the case with mine. There was no fix to be had, so I had to replace the main circuit board. That cost some dough.

 

[Tom Kershaw]

From an initial investigation I found the following underneath the front control panel:

Dead Link Removed

Dead Link Removed

This component seems to be inline before the on/off switch on the control panel. I may also try and find the Jobo's transformer.

Dead Link Removed



Tom.

 

[Photo Engineer]

Tom;

I think you nailed it in the frst two pictures. The burn marks are quite apparent.

That may be some sort of switch or fusing device. It looks like 4 cables are attached. The two plugs with two wires in the front, the single large cable and the ribbon cable. The heavy single cable appears to be able to carry a lot of power unless it is just a bundle of smaller cables. The back is not clear. There may be more wires there, but the bottom appears to have some screws making the cover removable.

Take a look inside that silver cover.

PE

 

[michaelbsc]

I looks suspiciously like an EFI capacitor, which shouldn't be that hard to replace. Of course, thats a diagnosis from afar with no real way to examine the machine. So, for a free diagnosis, figure it may be worth no more than you paid me.

 

[Tom Kershaw]

I looks suspiciously like an EFI capacitor, which shouldn't be that hard to replace. Of course, thats a diagnosis from afar with no real way to examine the machine. So, for a free diagnosis, figure it may be worth no more than you paid me.

Are you referring to the blue capacitor visible in the third image or the large metal component?

Tom.

 

[Steve Smith]

The large metal component with two wires in and two wires out (and hopefully, an earth connection) looks like an interference suppressor. It would have inductances in series with the live and neutral and capacitors between them and earth.

Something like this: http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0240696

Available from RS (but in a different package).



Steve.

 

[Frank Szabo]

Look at this - it appears to be the exact component you let the magic smoke out of (but appearances can be deceiving).

RS Catalog
Item #210-415
Page 2-3847

http://uk.rs-online.com/web/search/...gAV-_-0210415-_-Ovaloid equipment filter,6.5A

 

[Tom Kershaw]

The large metal component with two wires in and two wires out (and hopefully, an earth connection) looks like an interference suppressor. It would have inductances in series with the live and neutral and capacitors between them and earth.

I take it the interference suppressor capacitor (if that is what it is) could still contain current if it works in a similar fashion to a conventional capacitor?

Tom.

 

[Frank Szabo]

I take it the interference suppressor capacitor (if that is what it is) could still contain current if it works in a similar fashion to a conventional capacitor?

Tom.

It's probably bled somewhere in the circuit, but to be safe note the push-on connectors' positions, remove them with long nosed pliers, then take a piece of wire from the terminals to a good ground to discharge it.

No sense in jumping any higher than you have to. The machine already made you mad.

 

[Steve Smith]

I take it the interference suppressor capacitor (if that is what it is) could still contain current if it works in a similar fashion to a conventional capacitor?

No. They are small value capacitors on AC so will not store a charge and will be safe once the power is switched off.

Why couldn't I find that item Frank found a link to? It's much cheaper than the one I found!


Steve.

 

[Tom Kershaw]

No. They are small value capacitors on AC so will not store a charge and will be safe once the power is switched off.

Interesting. I just had another look at the component and can only see live and neutral connections.

 

[Frank Szabo]

No. They are small value capacitors on AC so will not store a charge and will be safe once the power is switched off.

Why couldn't I find that item Frank found a link to? It's much cheaper than the one I found!


Steve.

Steve - sometimes, there's a filter such as this upstream from a larger "smoothing" cap such as the 1000 mfd 25vdc in one of the photos. That puppy will definitely hold a charge if not bled off. Didn't know where it was in the circuit but was probably in the AC to DC area as a ripple filter and should be rather close to any line filters like this.

I'm sure the cagey Germans made sure it was bled down but ...

 

[Steve Smith]

Yes. But if it is the filter you gave a link to, it will be on the incoming 230 volt AC supply with inductors in line with the live and neutral and small capacitors in the L-N, L-E and N-E positions. The primary of the mains transformer will short these out so I wouldn't worry about residual charge as there will not be any.

Also the fact that the incoming and outgoing wires are brown and blue confirms that it is on the AC supply.

This is not the same as a large electrolytic in the DC supply which will hold a charge. The DC supply in this is not likely to be higher than 25 volts anyway so that wouldn't cause a problem.

In the valve (tube) circuits I make with HT of 250 - 450 volts, I put a 100K resistor across one of the capacitors to bleed the voltage down when it is switched off. This shouldn't be necessary in something like this with a relatively low DC voltage.

Although the device is shown with a connection for an earth wire, this is not actually necessary if it is bolted solidly to a chassis which is connected to earth.

Steve.

 

[Steve Smith]

Interesting. I just had another look at the component and can only see live and neutral connections.

If you look at your second picture (actually, you can look at the real thing!) you will see that there is a spare tab which is connected to the case but does not have a wire. Look at the component Frank linked to and you will see a similar central terminal at one end.

Getting a replacement is one thing but you need to determine if the reason for failure was just this filter failing or if something else caused it to fail.

Likely suspects could be the power transformer or a bridge rectifier on the secondary of the power transformer.

I personally would suspect the filter component itself reasoning that if the primary of the power transformer was short circuited, the fuse should have blown instead of the filter giving up.

Even so, it's difficult to be sure without actually being there poking around with a multimeter.


Steve.

 

[Tom Kershaw]

Even so, it's difficult to be sure without actually being there poking around with a multimeter.

Is there anything specific you would advise checking with a multimeter? I ask as the transformer is buried in the depths of the machine somewhere and will take some determination to access.

Tom.

 

[Steve Smith]

If you can determine which pair of wires going to the filter component are from the mains input (via a switch and fuse in the live) then the other pair are going to the transformer primary. Disconnect those from the filter and measure the resistance between them. Depending on the power of the transformer, its DC resistance should be around 30 - 100 ohms. If it is very low, say around ten or less then there is a problem.

If this appears to be o.k. Then I would suggest getting a replacement filter an fitting it.

Now the next bit of advice I am going to give is what I would do. If you are uncertain at all then have someone competent look at it for you.

I would replace the fuse with one of around half the rating specified, turn it on and see what happens. If it powers up o.k. and does not blow the fuse you are probably safe to fit the correct fuse and run the unit. If it does blow the fuse, you have other problems which would be very difficult to diagnose via the internet!

If you know someone who owns a Variac, that is another way of trying it. A Variac is a device which allows you to vary the AC voltage from 0 to 260 volts. Start at zero and slowly raise the voltage whilst monitoring current draw. If it gets excessive then stop. Actually, anyone who owns a Variac should know all of this and should be able to help you so there's no point me going into further detail!



Steve.

 

[Tom Kershaw]

I would replace the fuse with one of around half the rating specified

Internal fuse(s) or the fuse in the plug?

The Jobo is rated at 1300W, 1200W accounted for by the internal water heater.

 

[Steve Smith]

Good point. I hadn't thought about the heater. Can this be turned off?




Steve.

 

[Tom Kershaw]

Good point. I hadn't thought about the heater. Can this be turned off?

Yes, I think so. The processor has separate IEC connectors for the heater and control units; e.g. the control section can be powered by a UPS.

Tom.

 

[Steve Smith]

The problem of diagnosing via the internet is that I don't know the machine in question or your competence with electrical equipment repairs. I am likely to be accused, quite rightly, of suggesting things which may be dangerous if not approached safely and sensibly.

I would like to know if this machine just has one fuse (I'm refering to a fuse on the machine, not in the plug). If so, that fuse has to supply the current to the heaters and as such is too large to provide much protection from a fault in the power transformer/power supply circuit. The reason is that what would be considered a normal current flow for the machine with the heater switched on would be far in excess of the current needed to destroy the transformer should a fault arise.

If I had the machine here I would try to power up the transformer separately via a small (say 315mA T) fuse and see if the electronics side worked. If it did, I would connect it all up and try it properly.

If you are able to turn off the heater (heaters?) then I would do that and power it up with a 315mA or 500mA T fuse in place of the standard fuse.

All of this advice is inferior to actually letting a competent person look at it for you and is obviously at your own risk. If in doubt, don't do it!!



Steve.

 

[Steve Smith]

The processor has separate IEC connectors for the heater and control units; e.g. the control section can be powered by a UPS.

Why didn't I read this bit properly before answering?!!

You need to replace the filter component as discussed earlier and just power up the control section. Initially with a lower rating fuse if possible.


Steve.

 

[Tom Kershaw]

I suspect the DC section still draws a reasonable amount of current considering the number of motors, pumps etc.

Tom.

 

[Frank Szabo]

Tom:

I want to echo Steve's cautions - Regardless of what you do, think first and be careful.

You Brit fellows have (if I recall) 220VAC mains where here in the USA the household mains are 120VAC. 220V will "hold" you (muscle contraction) while 120 will only scare hell out of you but both can tie your tail in a knot if you're not careful.

You've already let the smoke out of your processor - don't let yours out! [grin]

 

[Steve Smith]

You Brit fellows have (if I recall) 220VAC mains

Even better than that. It's supposed to be 230v. sometimes it's 240.



Steve.