Mod for new Scooba Power Supply - 240v

[mfortuna]

What are the before and after values of the sense resistor?

What was D11 originally?

Thanks

I deleted the modification details after I found there was no people interesting in this article, I don't know how you
get this information. now, I recovered my last txtout.

I noticed when I posted my question your orginal post changed. You must have edited it while I was replying.

[red_sword_fish]

What are the before and after values of the sense resistor?

What was D11 originally?

Thanks

I deleted the modification details after I found there was no people interesting in this article, I don't know how you
get this information. now, I recovered my last txtout.

I noticed when I posted my question your orginal post changed. You must have edited it while I was replying.

So...everything changes at that moment~~~


the internal charging controllor use a independent 5VDC, and I think it works by comparing the voltage on pin 2 "Control" with the charge voltage, and drives a SCR for charging regulating, the Green LED shows status of charge controllor.

I'm not an electronic egineer, but a mechanical engineer
So, not each my point on electronics would be correct, If I made a mistake, Pls don't mind.
Hope these msg could help more Scooba's users who still using a 110/220 adaptor.

[Mabuse76]

Sorry for asking again, but I am only a "software" guy....
Is there the chance to get a *simple* step by step guide which components I have to modify to transform the scooba charger to 220V, maybe with a "shopping list" for the parts? Something like "e-tech for dummies" would be great

[Spirit Force]

Have you verified which version of the charger you have? If you ain't sure open it up and take a look. After that you'll know which mod instructions to follow. But be careful while opening it since you have used it, due to fact that there still might be some High Voltages present. The same goes for that white Roomba charger your thinking about modding.

[Gordon]

...Is there the chance to get a *simple* step by step guide which components I have to modify to transform the scooba charger to 220V, maybe with a "shopping list" for the parts?...

Assuming the PWB-assembly of your Scooba PSU looks like the unit in the pix on page one of this thread, you may use this information.
The essence of what you need is in this r_s_f post:
http://www.robotreviews.com/chat/viewto ... 081#p65081
The one item not precisely tied down is diode D11 for which r_s_f (red_sword_fish) suggested a 1N4001, or 1N400* as replacement options. The 1N4001 has a 50V, PIV (peak inverse voltage) rating, and is the lowest PIV in a family range of 1N4001, 1N4002, ..., 1N4007 (which has a 1000V PIV). I have the impression that r_s_f probably used the 1N4001, but was indicating that any of the higher-PIV diodes in the family would be fine (which is true) if the 1N4001 is not available.

You may remove the original varistor (14D271), which r_s_f called a "Voltage Sensed Resistor", and replace it with a 14D391 (next higher voltage) varistor, or simply omit the varistor from your revised circuit.

The e-caps (electrolytic capacitors) may be ordered using the listed capacitance, 47 microfarads, and 400V, working voltage. To obtain those parameters in a case that is not too large to fit under the bonnet, you may have to search for 'super-miniature' e-caps. While searching, also look for capacitor series that are very low in Equivalent Series Resistance, or the cap-series' info blurb claims the caps are built for SMPS (switch-mode power supply) application.

See the red-ellipse marked pix to identify where these parts are located (D11 is in the smallest ellipse). D11 & the e-caps are polarized, so pay attention to their original orientations and final orientations.

Creating a USA based "shopping list" for you takes time and could be a waste of time if you are still in Germany. Doesn't http://uk.rs-online.com/web/ serve you in that area?

[Mabuse76]

First I would like to thank you both for the input! Great support.

I was able to locate all the parts I need at a local electronic shop and am going to mod the roomba first this weekend. Concerning the scooba: Do you know this review: http://mysite.verizon.net/gsplews/26DCpwrSup.htm The argument that the EMS supression could be affected somewhat scares me.

I did open up the scooba adaptor, however the board has a different layout.There is one 100uF Elko, which I can easily sub with the 400V Version. However I can not find the Diode D11 (no D11 print on the board). Could it be that I will have to sub D12 and D13 diodes (see close up pics) with 1n4001 each?

see enclosed pics:

[Gordon]

...Concerning the scooba: Do you know this review: http://mysite.verizon.net/gsplews/26DCpwrSup.htm The argument that the EMS s{EMI} upression could be affected somewhat scares me.

Yes. That's my vintage 2006,Q1 stuff. That warning was based solely on my reading several pertinent application notes that Power Integrations provides for d/l. I had seen the experts' recommendations for SMPS 240VAC mains design, and appreciated that Company's attention to detail. I then took the case off my iRobot "Rapid Charger" -- a 2004 product that was designed to operate with mains voltages spanning 110VAC to 240VAC -- and inspected its SMPS section (a module that was not designed or built by iRobot). I was able to see external clues (mainly on the step-down transformer) showing attention to high-voltage design, and that told me the Rapid Charger's SMPS had been built in accordance with one AppNote's guidelines.

After comparing Rapid Charger SMPS construction to the 2004 Fast Charger PSU, and to the 2005 Scooba PSU, it was obvious that neither one was built with 220/240VAC mains drive in mind. Those units cost less than they would have if constructed for the higher voltage mains. I can see that was a reasonable choice by iRobot, because, in those years, 100% of Roomba/Scooba sales was to US & CA.

When I threw up the Scooba web pages in 2006,Q1 I was not comfortable with telling anyone to just go ahead and rework a Scooba PSU for 220/240VAC input, no problems will arise. I was well aware of the many 220/240VAC 'upgrades' to the Fast Charger PSU that had taken place, and, since the 2005 Scooba PSU uses basically the same circuit (they both use Power Integrations' switcher ICs) design, felt Scooba PSU mods should work OK too.

So, getting back to your 2005 Scooba PSU, just go ahead and sub in a higher voltage C1 e-cap, remove the varistor ("RV1") and omit it, or replace with a higher voltage rated varistor, leave the old fuse alone, and give the PSU a test run. If battery charging seems to be going well (always leave Tank off the robot while charging), and you can sense heating of the battery to confirm reasonable current is passing into it, then you could study whether the PSU might be an EMI problem for you, or to neighbors. Do that by operating all of your RF receivers. If you think you find some EMI effects, then operate the SPSU by powering it with your 220VAC to 110VAC step-down transformer (adapter) and determine whether there is a change in perceived interference.

I did open up the scooba adaptor, however the board has a different layout.There is one 100uF Elko, which I can easily sub with the 400V Version.

Bear in mind that C1 (if implemented correctly by iRobot) is not a "garden variety" e-cap. E.g., its not of a type that one might find inside a TV set (unless the set uses a SMPS as its dc-power source). The stored charge in C1 is being switched through the primary of the transformer (T1) at ~100,000 Hz rates, and that translates into special construction requirements that make the e-cap a little more expensive. Other than capacitance, and working voltage, and physical case size, the qualities you should be looking for are: low ESR, and / or "built for SMPS use". What's the down-side if you don't pay attention to that requirement? The e-cap will run hotter, and tend to fail sooner than later; not to mention, switch-mode conversion will be less than optimum (but, probably not so much that you would notice).

However I can not find the Diode D11 (no D11 print on the board).

Its a good thing that Spirit Force suggested you find out which Scooba PSU you intend to modify! Yours has no "D11" to R&R.

[Mabuse76]

Thanks Gordon!

So I will go ahead and cross my fingers that no diode is going to burn.

one last question about the caps. I found some at conrad.de, a retailer that is comparable to radioshack in the US. They are specifically intended for HF scenarios and switching power devices. (see specs http://www2.produktinfo.conrad.com/date ... 8X31_5.pdf)

However while they do stock the 47uF / 400V, there is no replacement for the 100uF Cap built in the Scoopa PSD rated @ 400V. Since the voltage is doubled, isn't it that the 47uF should be fine as a replacement, too, since the charge is high enough?

[Gordon]

...about the caps. I found some at conrad.de, a retailer that is comparable to radioshack in the US.

IMHO, Rad-Shack is no longer a useful component supplier (they have taken the more lucrative path of selling consumer electronics!). But, the e-cap you have found does look like it will serve. The specs seem to imply use of that cap as a filter (since that is what the ripple data relates to), and I don't know how well it will serve as the H-V input storage device for the switcher, which is probably subjecting / imposing more than "850mV" PP ripple. That's the action that heats a capacitor. Go ahead and install it and give it a run to see what it does. We can cook up a way to check whether its temperature is higher than 100C, if you wish.

... while they do stock the 47uF / 400V, there is no replacement for the 100uF Cap built in the Scoopa PS ... Since the voltage is doubled, isn't it that the 47uF should be fine as a replacement, too, since the charge is high enough?

Right. That option has been suggested before in these fora. I would try it, and expect all to be OK when 240VAC powered. Just don't expect the PSU to work with 110-120VAC input.

[red_sword_fish]

I did open up the scooba adaptor, however the board has a different layout.There is one 100uF Elko, which I can easily sub with the 400V Version. However I can not find the Diode D11 (no D11 print on the board). Could it be that I will have to sub D12 and D13 diodes (see close up pics) with 1n4001 each?

I think you could check and find out which Diode is directly connect to the U3 [ who is a 7805 ], then you can replace it with a 1N4001, otherwise, the diode may burn out and the charger will not work after AC220V was used.

[Mabuse76]

I think you could check and find out which Diode is directly connect to the U3 [ who is a 7805 ], then you can replace it with a 1N4001, otherwise, the diode may burn out and the charger will not work after AC220V was used.

Thanks for the hint. I will do that once I receive all the ordered parts and will keep you posted about my results....

[Gordon]

Mabuse76, when you said this, a few posts back:

... I did open up the scooba adaptor, however the board has a different layout.There is one 100uF Elko, which I can easily sub with the 400V Version. However I can not find the Diode D11 (no D11 print on the board)... .

I should have pointed out that we are now deviating from this thread's topic! I've changed my post-heading to reflect that deviation, but can't expect much help by that tactic. Future readers will simply have to pay more attention while reading this 'history' in order to know whether original, or newer (2008 & later) Scooba PSUs are being discussed!

Now then, you have seen r_s_f's post, which asserts that the original Scooba PSU circuit contains a "7805", five-volt regulator IC at position "U3". Here's a copy of his statement:

I think you could check and find out which Diode is directly connect to the U3 [ who is a 7805 ], then you can ...

He's quite firm about that 7805 being in his PSU, however, I find in my PSU (I'll list its pedigree shortly) a TL431 at U3, and I'm fairly certain you will see too, a device marked "...TL431...", rather than "7805".

The TL431 is a three-terminal adjustable voltage regulator, so it can be set up to function in a way similar to the fixed-voltage regulation done by the 7805 (but, to do so would be a waste of its capability).

To sort out whether iRobot has built some intermediate-vintage SMPS that uses a Power Integrations, Inc., TopSWITCH IC-switcher in the HV section, but also makes use of a 7805 regulator in the LV section, I must ask l_s_f two questions: 1) l_s_f, do you have two Scooba PSUs that you have modified for 240VAC, or just one; and, IF TWO, what is the date-code marked on the PCB of the intermediate-vintage PSU (the one using at U1 a 7-pin, TOP246Y, and at U3, a 7805 IC)?

Here are my original SPSU's credentials:
Model: 13143.
PCB production date (ink stenciled on the PCB): 6/7/2005.
Case-colors: Both gray (with first released 5900s) and light blue (with
5800s and Q2,2006 5900-Scoobas).

And now, since I have blown much of Saturday away tracing tracks around U3, I must force onto all of you a summary of my findings!

For anyone actually interested in this, you should google for "TL431 data sheet". If you come across one from National Semi., keep looking (for Fairchild, or AIC) since National has numbered the 431's TO-92 pins out of order (but, pin names are OK).

U3, pin-1 (U3-1) is nearest to the PCB edge, being about 6mm inset. So,
U3-2, and U3-3 sequence toward the card's interior.
U3-1 = VREF, or "R".
U3-2 = Anode, or "A".
U3-3 = Cathode, or "K".
When I write track notes, I like to use U3K, U3A, and U3R, in place of the pin-numbering nomenclature.

If you d/l a pdf data-sheet, you will see the schematic symbol assigned to these adjustable regulators. It is like a Zener diode symbol, but with the VREF terminal being shown as a line connecting to the filled diode-triangle part of a Zener's symbol.

My tracing efforts of U3 connections to associate components was generally limited to the three nodes to which U3's pins connect, therefore, giving a very incomplete picture of what all the TL431 is doing in this circuit. I'll mention that the same device is used in Roomba-4XXX Fast Chargers, so I was interested in learning the differences between the 431's actions in the two circuits. All I can say about that, now, is Scooba's LV-section is more complex.

I see that U3 is powered by the CTRL signal that is output by Scooba. The CTRL signal comes in at J4, then passes through D13 and into U3K, hence the supply voltage that U3 has to work with is determined by the robot's charging-control system. D13 appears to be a 1N4148 signal diode (500mW MAX, 200mA MAX, 100V_recur MAX); as is D12.

Since U3K is on the same node as U2K (pin-2 of the 4-pin opto-isolator), the voltage on that node modulates U2's LED current, which, in turn, modulates what the TOP246Y switcher is doing for the voltage regulation.

U3A, the power return side of U3 connects to what I would call "+22Vdc_RTN", sort of a local GND (which in the 4XXX-ckt, passes current through the Fast Charger's current shunt, prior to returning to the secondary winding).

U3R looks to be driven by Q1's emitter (through R15), but I have no idea which control parameter runs the base of Q1.

The above cursory inspection tends to show me that the original Scooba-PSU's U3, and the pair of diodes that connect to it, are as isolated from the high-voltage section as is the Fast Charger's "U3". It is difficult to dream up a damage scenario in this circuit that might be related to re-working the HV-section for larger mains voltage input.

[red_sword_fish]

Gordon;

I think you are right, I should not firmly say that is a 7805, I just guess, but...everything is posible.

I am sure my charger of Scooba works again after I found D11 was destroied.

I need correct my point with:

if u find a diode directly connect between an output pin of transformer to a 78L05, it might be the "D11" which should be replaced.

I have 2 of iRobot, one is a Scooba, another is a Roomba. Charger for Scooba was modified, and the Charger
for Roomba 560 is not modified yet, tomorrow I will recieve all parts I need, and I will do it in two days.

BTW, fuction of D11 in charger of Roomba is as same as it designed in charger of Scooba, it should be replaced also.

the two iRobot charger all use 78L05, details pls find the following pic.
it seems that the 431 has something to do with the opital-couple chip?



My Scooba:

already modified to suits for 220VAC:

[red_sword_fish]

My Roomba 560:

Roomba 560 Label.JPG (13.91 KiB) Viewed 14358 times

[Gordon]

r_s_f, thank you very much for the clarifying pix. Those are great photos! Your top-side illumination has produced the best full-board pix of these assemblies that I have seen!

The use of regulator 78L05 in the more recent Roomba/Scooba SMPS is well confirmed.

Good luck with the next conversion!

---Gordon

[red_sword_fish]

r_s_f, thank you very much for the clarifying pix. Those are great photos! Your top-side illumination has produced the best full-board pix of these assemblies that I have seen!

The use of regulator 78L05 in the more recent Roomba/Scooba SMPS is well confirmed.

Good luck with the next conversion!

---Gordon

I should say thank you, Gordon!
Without your help and important infomation, my Scooba charger could not be repaired OK!

now, modification on Roomba is successed!
Pls see followed pic:

[echo]

Greetings from yet another 240V country - India. Successfully modded Roomba 550 adapter to 240V by changing 3 items as suggested by red_sword_fish. I followed rsf's instructions as those images were the only ones I found that were identical to the insides of my charger - board "WHE-59 VER1.0"
1. Changed C1 to 47uF 400V
2. Changed RV1 to 14D391
3. Changed D11 to 1N400*

Thanks to red_sword_fish and everyone who have posted instructions on how to mod the chargers and a very big thank you to Gordon who is the common factor in all these threads.

[Fraggboy]

echo,

Welcome.JPG (7.41 KiB) Viewed 14036 times

Glad you were able to mod your PS! We have a lot of talented members here!!

Hope to see you around the forums!!

[echo]

Thanks, Fraggboy. Indeed, there are a lot of great talents here.

[borderline1]

hi there
i just got my new roomba 560 and a scooba.
since i live in a 220v country i found these forums and information most enlightening.
after checking and inspecting i have found that my roomba charger was a typical charger but the scooba charger was one of the new models L13143 model which contains as follows:
C1 is 2 47uf
and rv1
i have replaced the 2 capacitors with 1 100uf 400v.
and since i could not get a 400v varistor replaced the original with 420v varistor.
checked the charger for a minute and it seems to work.
after reading this thread and others i understand i should continue as follows:
change d11 diode as recommended above
replace the fuse near the varistor from 250v to higher rated fuse of 1.6A
since i am a novice at this i would like to verify the above and get some confirmation before continuing and also to inquire if i should do the same (diode and fuse)??

would be most grateful for any comment and ratification of my intended actions

B