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 Post subject: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Sat 02, 2013 6:19 pm 
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Location: Montgomery, Louisiana
I just purchased an LKB 2103 Electrophoresis Power Supply. Naturally the thing does not have any output. I need a schematic diagram if anyone has one and any other info as well. It is mid-1970's vintage and is all solid state.

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Mon 04, 2013 12:26 pm 
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Location: Powell River BC Canada
The amateur DNA sequencer crowd may have one. Did you buy a sequencer or just the power supply?

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Mon 04, 2013 12:35 pm 
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Location: Johnston, Iowa
Many of the power supplies used for electrophoresis will not work without a load. If you turn it on and put your multimeter into the output receptacles you will not get a reading. I've run thousands of gels and almost all the power supplies I've seen work this way. This is a safety feature, if you unplug the leads while the gel is running they immediately shut down.
Keith


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Mon 04, 2013 2:57 pm 
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I have several electrophoresis supplies.

They all work just like any other supply... full output regardless of load.

This is not to say that the above descriptions are wrong, only that they're not universally applicable.

- Leigh

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Mon 04, 2013 3:52 pm 
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LKB/Bromma electrophoresis supplies, at least all I have come across, have optical sensors inside that go across all the output connectors. LKB connector wires have a long plastic end that blocks the optical sensor and triggers the output on when the cables are fully plugged in. On mine, I went in and bypassed all the sensors by covering them with heat shrink tubing. These supplies work well, but be very careful with them. I found an operating manual for my 2197, but service data for LKB equipment is very scarce. The company that bought LKB out did not retain nor make any legacy equipment service data available.

-Mark-


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Mon 04, 2013 7:17 pm 
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I only have one electrophoresis power supply, but it has another safety feature to be aware of.

It is a LKB-ECPS3000-150. That is 3KV and 150 Watts.
"Leakage" can shut down the output, on mine there is a red led that goes on when the ps is cut-off due to leakage.
In this case, leakage is 'ground fault current' detected as the difference between the current out the positive terminal vs. the current in at the negative terminal. The power supply has an internal center-tap tied to ground.
The intended electrophoresis cell loads are expected to be floating from ground.

I can't blame them for having all these safety features; considering they are for use on "wet bar" biology lab benches.

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Mon 04, 2013 8:45 pm 
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Another quirk to be aware of that might happen is with my 2197, it always powers on up to full output voltage, then drops to the set regulated voltage/power. You can't leave something connected and shut it off, then power back on again unless you desire to kill whatever is connected to it.

-Mark-


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Tue 05, 2013 3:03 am 
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Location: Montgomery, Louisiana
I figured out what the problem is! :mrgreen:

There is an interlock connector on the rear panel. It has a red and black wire. I measured 1 Vdc on the red and the black is grounded. I shorted the red to black with a 220 ohm resistor, but nothing happened. I shorted my meter probe across them and got some output. Then I used a piece of 18 gauge solid copper wire to short it and the thing started to work just fine. Apparently there was a safety lock of sorts that had to be plugged into it. I get voltage at the terminals with or without a load.

I emailed the Biochrom company, but they didn't have any info.

This is a switching type of supply and it works at about 45 kHz. There is also some substantial 60 Hz hum to it. I may have to rig up a filter for it. Any suggestions?

There is also a wattage setting. You can set it for a particular wattage and it will not go over it, no matter the combination of resistance and voltage.

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Tue 05, 2013 4:40 am 
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NantachieRat wrote:
I figured out what the problem is! :mrgreen:

There is an interlock connector on the rear panel. It has a red and black wire. I measured 1 Vdc on the red and the black is grounded. I shorted the red to black with a 220 ohm resistor, but nothing happened. I shorted my meter probe across them and got some output. Then I used a piece of 18 gauge solid copper wire to short it and the thing started to work just fine. Apparently there was a safety lock of sorts that had to be plugged into it. I get voltage at the terminals with or without a load.
Sounds like a simple external-relay on/off control.

NantachieRat wrote:
This is a switching type of supply and it works at about 45 kHz. There is also some substantial 60 Hz hum to it. I may have to rig up a filter for it. Any suggestions?
Sorry, no.

All of mine are just standard regulated power supplies with very clean output voltage.

- Leigh

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Tue 05, 2013 8:01 am 
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Location: Powell River BC Canada
Then I used a piece of 18 gauge solid copper wire to short it and the thing started to work just fine.

Seen on the wall of a radar station:

He who shorts interlocks ends up in a pine box :mrgreen:

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Tue 05, 2013 2:01 pm 
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The 2197 has the interlock on the back also, it is just a plastic encased "key." Be thankful your older model didn't have the optical sensors also. The only way to adapt these supplies for other purposes is to bypass these items. The 2197 is a switching supply also, but the primary end of it is a hefty current 50 volt linear supply that is well filtered. I checked it, and there is no noticeable ripple in the output on this model. I don't imagine for the original purpose they had to be well filtered, so some makes/models might need some additional output filtering to make them useful as bench supplies.

-Mark-


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Tue 05, 2013 11:31 pm 
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radiotechnician wrote:
Then I used a piece of 18 gauge solid copper wire to short it and the thing started to work just fine.

Seen on the wall of a radar station:

He who shorts interlocks ends up in a pine box :mrgreen:


I don't want to end up in a pine box!

What would be better than shorting the interlock terminals?

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David D. Poston, Mad Scientist
Montgomery, Louisiana


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Tue 05, 2013 11:43 pm 
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MarkPalmer wrote:
The 2197 has the interlock on the back also, it is just a plastic encased "key." Be thankful your older model didn't have the optical sensors also. The only way to adapt these supplies for other purposes is to bypass these items. The 2197 is a switching supply also, but the primary end of it is a hefty current 50 volt linear supply that is well filtered. I checked it, and there is no noticeable ripple in the output on this model. I don't imagine for the original purpose they had to be well filtered, so some makes/models might need some additional output filtering to make them useful as bench supplies.

-Mark-


I have been experimenting with tuned chokes and they seem to work very well. It is basically a tank circuit that resonates at the ripple frequency connected in series with the output. I am thinking of rigging one up and connecting it to my output and see how it works.

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Wed 06, 2013 12:22 am 
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Joined: Sep Thu 23, 2010 6:37 am
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Location: Powell River BC Canada
Your new power supply will be fine for experimenting with photo multiplier tubes, and common
cathode ray tubes from oscilloscopes.

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Thu 07, 2013 2:29 pm 
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Joined: Nov Thu 22, 2007 11:31 pm
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Location: Johnston, Iowa
Quote:
have several electrophoresis supplies.

They all work just like any other supply... full output regardless of load.

This is not to say that the above descriptions are wrong, only that they're not universally applicable.

- Leigh

Definitely true for the older power supplies. If you're going to buy one for your lab bench go for a older model. Where I work we have hundreds of gel power supplies and our benches are frequently wet. All of the new power supplies that we have are loaded with safety features. It's been years since I've seen one without safety features. Where I work Bio-rad are the most common power supplies.
Keith


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Thu 07, 2013 5:18 pm 
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keith49vj3 wrote:
Definitely true for the older power supplies. If you're going to buy one for your lab bench go for a older model.
I only buy electrophoresis supplies with regular banana jacks for the output.

This probably distinguishes "new" style from "old" style supplies.
The banana era supplies don't have any obvious safety features.

- Leigh

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Nov Thu 07, 2013 6:02 pm 
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That is what I ended up doing on the Bromma 2197, removing the factory output connector setup and replacing it with standard banana jacks. The supply was given to me for free, it ended up being worth a few bucks in parts and a few hours of putzing around with. It doesn't get much use, but is something that is there if needed.

-Mark-


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Jun Tue 11, 2019 10:17 am 
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Joined: Jun Tue 11, 2019 9:59 am
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Willitwork wrote:
I only have one electrophoresis power supply, but it has another safety feature to be aware of.

It is a LKB-ECPS3000-150. That is 3KV and 150 Watts.
"Leakage" can shut down the output, on mine there is a red led that goes on when the ps is cut-off due to leakage.
In this case, leakage is 'ground fault current' detected as the difference between the current out the positive terminal vs. the current in at the negative terminal. The power supply has an internal center-tap tied to ground.
The intended electrophoresis cell loads are expected to be floating from ground.

I can't blame them for having all these safety features; considering they are for use on "wet bar" biology lab benches.


I've had the same problem with the interlock which I solved but I am also having a problem with ground leakage. I understand that the supply shuts down if there is a leakage of more than .5mA. The unit works fine in smaller cells but I am working with a large one, 4x5 meters it is for an art installation and I need the high voltage to accelerate the particle migration which is why I am using an electrophoresis power supply. What is a way to bypass this ground leakage safety. All this is new to me, including posting in forums, I hope I can still use the 6 year old thread...


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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Jun Wed 12, 2019 5:34 am 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 11821
Location: Powell River BC Canada
In the supply rated at "It is a LKB-ECPS3000-150. That is 3KV and 150 Watts" ,
the current is 150 / 3000 the current 0.05 Amps.

Apparently yours is larger. 0.1 to 0.2 is cosindered lethal.

3000 volts is more than ample a path through human skin.

You need safety engineering.

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 Post subject: Re: LKB 2103 Electrophoresis Power Supply Schematic/Advice
PostPosted: Jun Wed 12, 2019 1:27 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
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Location: Sunbury, Ohio 43074
NantachieRat wrote:
radiotechnician wrote:
Then I used a piece of 18 gauge solid copper wire to short it and the thing started to work just fine.
Seen on the wall of a radar station: He who shorts interlocks ends up in a pine box :mrgreen:

I don't want to end up in a pine box! What would be better than shorting the interlock terminals?

Well, this time you may have gotten away with it. After the fact, you're still alive! :shock: Your fix seems to be OK as-is .... the issue is, shorting out interlocks without knowing what they are, or what they are for, can leave you existing as nothing more than a brief puff of smoke.

Try that with a transmitter of any power (the 2KW C band uplink I used to operate comes to mind), and you'll get thrown across the room before you flame out. Or get your knee caps blown off. Do be careful!! :)

This more or less equates to "fixing" a blown fuse with wire, or a penny, until you are SURE it's just an interlock

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