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avatar: rhozee
rhozee
2 posts
Replied to rhozee's post on February 26th, 2014

We've had the 5415R for many years. It seems that no one in the lab ever turned it off (it has always been ON). Well, I turned it off and unplugged it the other day in order to clean the rotor.

Now it will not turn back on. I've tried replacing the fuse (slow blow 6.25A, 250 V), but that did not work.

Is there anything else I can check? I did notice that the fuse holder had positions for two fuses, but only one was occupied (I tried putting in two, but could not get everything to fit back in when two were in place).

Thanks for your attention and help!

 

avatar: Bert
Bert
8 posts
Replied to rhozee's post on February 26th, 2014

If your unit is really dead, start at the basics:

Follow the power input line. Cable terminal, switch ( in and out) / fuse holder, noise filter,  power supply input connector. If you do your measurments hot, be extremly careful. I prefer to measure it by ohm-meter. You can disconnect the power supply connector and do your resistance measurment over the complete setup.

Bert

avatar: JJablonski
JJablonski
5 posts
Replied to rhozee's post on June 24th, 2014

I have 5 of these models all experiencing the same problem.  I took them apart and examined.  There are 2 boards.  The power board located directly where the plug enters and the control board that is mounted behind the display.  The larger ribbon conector attaches the control board to the power board.  I noticed that if I disconnect that ribbon conector from the power board and plug the centrifuge in, I get a green and red LED that light up on the power board.  I then re-connected the ribbon cable to the power board while it was hot and then the display worked and the LED lights also stayed illuminated and everything was fine.  This is a temporary fix that worked on them all.  The only problem is that if the power is turned off for longer than a certain amount of time, this needs to be re-done.  Great caution needs to be taken so you don't kink any of the cables when putting back together, and also there is a risk of working with it while it has power applied to it.  I know this is an old post, but wanted to see if there was any new information on the subject since I want a more permanent fix.

avatar: rhozee
rhozee
2 posts
Replied to JJablonski's post on June 25th, 2014

Thanks so much for the information!

Update: we can’t find an easy way to access the control board (and ribbon cable) for the display panel.   We removed four screws from the plastic covering, believing this would allow us to remove the cover and access the boards.  We can’t find the right method to remove the cover, though.  Can you provide advice?  
avatar: JJablonski
JJablonski
5 posts
Replied to rhozee's post on June 25th, 2014

Yes, I have the instructions for disassembly.  The lid must be completely removed and then with those 4 screws removed, the entire shell pulls up.  I can send the pdf instructions to an email address if you provide one.  Email me at jjablons@scripps.edu

avatar: Murali
Murali
1 posts
Replied to rhozee's post on September 19th, 2014

Hi, I am experiencing the same problem. My 5415D was powered off for a month or so and it does not poweron. Could you please send me instructions for disassembly so that I can try your suggestion. 

Thanks, 

avatar: InnoWart
InnoWart
6 posts
Replied to rhozee's post on February 27th, 2015

Dear rhozee, I have the same problem ina two 5415d. First they displaied a Error 17. I changed the control board but the fault still occur. Have you the service manual or electrical scheme of this centrifuge?

Regards!

avatar: floyd
floyd
65 posts
Replied to rhozee's post on February 27th, 2015

It only reqires the one fuse. put it baack the original way and it should work. call 713-320-5812 if you need some more help

avatar: InnoWart
InnoWart
6 posts
Replied to rhozee's post on February 27th, 2015

Dear floyd. Thank you for your reply.

Are you sure that the problem is the fuse? It has the two fuses allowed right and the unit turns on, but in one of them appears Error 17 in the display and in the other the display don't light and I can hear a sharp beep (from the condenser).

Regards!

avatar: Geords
Geords
12 posts
Replied to JJablonski's post on August 14th, 2015

We have the same case on our eppendorf 5415 R,C and D. All are the same thing! When you disconnect the ribbon cable to the main board you can see the LED lights goes on and after a few second connect the ribbon cable and everything is back to normal, but everytime you turn OFF the power and turned ON the power again while the ribbon cable is connected, there is no display again and you cannot operate the unit again.

I agree to JJablonski with the temporary fix, coz i also did that, just remmember that it is risky and you should pay attention on re assembling the unit again.

I contacted Eppendorf for this problem, they could not give me a straight answer wheater the problem is short on the display board or a short in the main board.

We have an extra brand new display board. I did connect it to the main board but still, same thing happen.

Well the last thing i did not do is to replace the main board which cost for about $ 1,400 canadian plus tax and shipping.

I was hoping that Eppendorf will be a little bit flexible on assissting me to the problem since we have so many of them, well their answer was that i need to send it to them so that they can assess the problem and and replace those defective parts. Which parts? well the did not give me the definite answer.

I hope that when somebody had find a way to solve this problem will share it, so that it will be helpful to others like me.

Geords22

 

avatar: Geords
Geords
12 posts
Posted August 17th, 2015

Hello Dave,

Thank you for the reply. Well i already ask eppendorf about the main board price here in canada and it cost about 1387 canadian dollars.

I really would like to replace the board and also want to gain experience on this problem. Well the end user is not willing to buy the main board since the brand new unit only cost for about 3,500 dollars. 

If i find any development on this problem i will definitely post it to help orthers.

Geords22

 

avatar: InnoWart
InnoWart
6 posts
Replied to rhozee's post on September 2nd, 2015

Good job Bryan! That's great!

Would you guive some images about the components in the PCB to locate easy in it? specially the 47k resistor that you suggest to replace.

Thanks for your help.

avatar: Geords
Geords
12 posts
Replied to InnoWart's post on September 2nd, 2015

Nice work Bryan, it would greatly help me and others too!!!

Ill try to do what you have mentioned!

Can you provide some pictures of the resistor and location if possible?

Thanks again!!!

Geords

avatar: Geords
Geords
12 posts
Replied to Geords post on September 2nd, 2015

Posted By: Bryan Venema
Subject: Unit will no longer power ON
Message:

Solution !

I have an Eppendorf 5415 R that exhibits the same symptoms you describe.  Thanks for the display board ribbon cable tip.  That led me to investigate the circuit generating the voltage for the display board.  The UC2844 Current Mode PWM Controller IC (between C816 and C824) is being powered from 155v through four 47k resistors in series.  This is too much resistance as the UC2844 has an undervoltage lockout of 16v and when it tries to start the input voltage drops below 16v.  The actual cutout voltage has some variation and the design seems to be marginal.  The total resistance should be about 50k or so instead of 200k.  I just shorted out three of the 47k resistors (leaving 47k remaining) and now it starts every time.  This does put about .4 watts through the remaining resistor which is a little high but should be ok.  If you want to be more thorough you could replace each 47k resistor with a 12k resistor putting only .1 watts through each resistor.

Bryan

    From Bryan Guys!!!
avatar: The Seeker
The Seeker
2 posts
Replied to Geords post on December 2nd, 2015

Thank you very much!  That is of great help!  Is there any way you could provide some images of the resistors and location?  I found the IC.  Thank you very much.

avatar: jah
jah
1 posts
Replied to The Seeker's post on March 21st, 2016

Hi, were you able to determine the location of the 47k resistors?

 

Thanks

avatar: mikehope61
mikehope61
3 posts
Replied to jah's post on March 21st, 2016

I can't figure out how to paste a photo in this thread.

Email me if you would like an image of the resistor location.

 

thehopesathome@yahoo.com

 

avatar: Bryan Venema
Bryan Venema
3 posts
Replied to rhozee's post on March 21st, 2016

I originally took down my post of the repair because I had to modify the repair but then never went back and revised it.  The voltage is too low at 155v to power the UC2844 through the four 47k resistors so I shorted out three of the resistors to get it to start and it works fine and shoudl dissipate .4 watts through the 47k resistor.  However, on my centrifuge the voltage jumped up to 320v (?) when the rotor got up to speed and then dissipated 2 watts in my 47k resistor.  You can try using a large wattage resistor but you have tomake sure that you can dissipate the 2 watts of heat and the supply has to be able to continuously put 320v across 47k.  I was uncomfortable with this so I made a simple circuit to short out three of the 47k resistors when the voltage is low but then open up when the voltage increases.  I will email a .pdf of my memory of the kludge circuit to anyone that wants it.

venemab@uw.edu

avatar: mikehope61
mikehope61
3 posts
Replied to Bryan Venema's post on March 22nd, 2016

I made a string of three resistors in series, each one equal to 15K ohms. I then put this across three of the four original 47K resistors. So I left all four of the original resistors in place. I only placed the new resistor string across three of the originals, because I could not get the soldering iron in the tight canyon to the end of the fourth resistor.

 

This has worked fine for over six months so far.

avatar: Simba
Simba
42 posts
Replied to mikehope61's post on March 23rd, 2016

I have done extensive research and repair on these units.  I can repair the Converter PCB.  Very common problem with these units.  Labor and parts will cost under $350. 

avatar: Simba
Simba
42 posts
Replied to mikehope61's post on March 23rd, 2016

Phoenix Equipment in Rochester, NY can repair these units for under $350

avatar: ErikC
ErikC
1 posts
Replied to mikehope61's post on August 25th, 2016

Hi,

Most of the time the 47k resistors are not the problem. The problem is the 22uF/35V cap close to the converter. Just replace it with a new one.

Erik

avatar: Cothor
Cothor
3 posts
Replied to ErikC's post on November 29th, 2016

Hi,

I'd like to second the idea that the problem may be with the 22uF/35V cap.

While doing my troubleshooting, I discovered that in order to drop the voltage to an appropriate value for the 5V regulator, they've instituted a series of resistors.  This is a bit of a design gamble.  Yes, technically it will work to drop the voltages, but it will be vulnerable to sources of resistance in series or parallel to it (as compared to having a second appropriate regulator to step down the voltage prior to the 5V regulator).

Right beside the 5V regulator there are two capacitors, the shortest of which is a 22uF 35V capacitor that seems to be for filtering. I tested this capacitor and while it showed a 22.4uF value, and a low leakage, it had an ESR of around 850 ohms.  This would have been in parallel to the series resistor network and really messed with the resistance value designed to drop that voltage.

I replaced the capacitor with one that we had available (100uF 35V Electrolytic, which should still be reasonable for a filter capacitor) and the unit now powers up just fine.  The good news is that the capacitor is close to the non-hinge side of the daughter board, so it is easy to replace.

If you don't have a capacitor tester that will test Value/Leakage/ESR like our shop, it would be a good idea to stock a few extra 22uF 35V electrolytic caps.  At worst, it costs you all of 15c to try a simple fix.

**Note: The huge black capacitor would be sitting well over 120V and should be considered to be very dangerous/potentially lethal.  If you do not do electronics repair work on a regular basis, I recommend you get an expert to look over the board and perform this fix. 

Best of luck!

avatar: wbeaty
wbeaty
18 posts
Replied to rhozee's post on April 14th, 2017

Quote rhozee

turned it off and unplugged it the other day    now it will not turn back on.

 

It's the 2.2uF capacitor in the supply-boot circuit (or, 22uF on much later units.)   Symptom:  unplug the ribbon cable to the LCD, then power up again, it works fine. 

The supply is flaky, won't cold-start when under load.  It might work OK for weeks, then won't wake up if AC power was interrupted.  That failed capacitor overheats, goes bad, then the boot section of the supply barely "kicks on."   (Or doesn't.)   Then, the centrifuge will stay alive as long as it's never unplugged, or power never fails.

Replace the bad capacitor with anything between 10uF and 100uF, 25v or higher.  Calcs show that 220uF is too large, 1uF is too small.  (Don't reverse the polarity, it's an electrolytic.)   I posted complete details for 5415D here, it might apply to other 5414/5415 models.

 

DANGER: THE ENTIRE BOARD IS EITHER LIVE 120V, OR FLOATS AT 170VDC!
If you don't work with such things daily, don't mess with this pcb while it's plugged in. Only the "isolated" section marked in the photo isn't live-hot-dangerous. Note that over 1min is required for the large 560uF capacitor to discharge down from 170VDC.

Also see FULL SIZE IMAGE: http://staff.washington.edu/wbeaty/epndf5415D_1.jpg

location of bad 2.2uF cap

 

avatar: Paul Moyer
Paul Moyer
18 posts
Replied to rhozee's post on April 14th, 2017

By chance have you tried plugging it in to another outlet? Strange things happen sometimes.

 

Paul

avatar: KR8
KR8
2 posts
Replied to wbeaty's post on April 27th, 2017

Hi Bill, 

Thanks for all the info on this centrifuge. I'm not at all electronically inclined, so just to make sure I'm understanding this correctly: if I disconnect and reconnect the ribbon cable from the LCD, the centrifuge should work until it's powered off again? Is the ribbon cable shown in you picture? Again, I really don't know what I'm doing, just trying to get this thing working again.

Thanks,

KR

avatar: JJablonski
JJablonski
5 posts
Replied to KR8's post on April 27th, 2017

Hi,

I am the one who originally came up with the ribbon cable fix.  Email me at jjablons@scripps.edu and I will send you the instructions.

-Joe

avatar: wbeaty
wbeaty
18 posts
Replied to KR8's post on April 27th, 2017

Quote KR8

really don't know what I'm doing, just trying to get this thing working again.

 

You'd have to work with live 120VAC.  Dangerous for the inexperienced.

The ribbon connector is to the right of the photo, in the fuzzy area, marked CONN FOR LCD/CTRLR

To get it temporarily working, you have to power it up while the ribbon cable is disconnected.  Then, with 120VAC still applied, plug the ribbon cable back in.  The system then stays alive until turned off.   (All this is done with the cover removed!!)

It's easier to just to replace the bad 22uF capacitor.

 

avatar: wbeaty
wbeaty
18 posts
Replied to JJablonski's post on April 27th, 2017

Quote JJablonski

I am the one who originally came up

Great minds think alike!

I discovered the same thing last year, then tracked down the problem as the 22uF cap being baked by the hot 5V regulator.  I just found this thread last week.  see http://staff.washington.edu/wbeaty/chem-eppndrf.html

 

avatar: JJablonski
JJablonski
5 posts
Replied to wbeaty's post on April 27th, 2017

It's funny how that works out sometimes.  Many great inventions were discovered similarly.  I'm very grateful to see your permanent fix.  I haven't even checked out my machines since I posted back in 2014, but I'm sure the power has gone off since then.  Maybe I'll revisit them and swap out the cap in them all. Thanks again!