Sino DRO Display fault, ideas for repair?

I have an 'SDS2-2L' 2 Axis Sino control/display unit and although it is 99% functional, the fault that is exhibits prevents it being much use!

I have tested as much as I can, (electrolytics, switches, resistors etc) and visually examined the board and soldering and all the button presses are seen by the electronics. Two things stop it being usable, one is that it will not store the setup details in the NVR, and also one button totally blanks the display when instead of carrying out its function.

I have searched but doubt very much whether I will find the schematic, I just wondered whether on the offchance anyone here knows of any cost effective way of getting a repair done?

Ian P

> Two things stop it being usable, one is that it will not store the setup details in the NVR, and also one button totally blanks the display when instead of carrying out its function.

Is it old? The problem with NVR (usually flash or low-voltage EEPROM is that, although it has become much better in the last ten years or so) is that it has a limited cycle life. I noticed this on the stereo of my last car which started to 'forget' the last used volume and always came on very quiet. If this has happened, there's not really anything you can do as it's normally built into the microcontroller and replacing it won't be any good as you need it programmed as well.

The dodgy button may be solvable, it could be a bit of corrosion or contamination causing it to short the wrong pins.

My advice would be dismantle and clean carefully with IPA, dry thoroughly in a warm place, and see it it helps.

If both problems are due to corruption of the internal programme, then there won't be a lot you can do.

Neil.

Just a guess but have a look and see if you can identify a battery on the PCB.

Dave

Give these guys a ring:- **LINK**

Neil

I think your last sentence is the most likely scenario

The unit is an new and has never been used, I bought it some time ago from a dealer as 'ex display, faulty' (still has the original clingfilm stuff over its facia). I have connected two rotary encoders to it and both axes work, I can zero them and use quite a few other functions. Tomorrow I should get two magnetic encoder that I will put on my lathe but I doubt I would be so lucky to find that the default resolution will be correct for my scales.

There is no memory backup battery, the values are stored in the usual 8 pin EEPROM. The board has a 40 pin cpu and a few surface mount LSI chips which are probably proprietary so without information from the manufacturer I can only use trial and error techniques which so far have not worked.

The button that blanks the display is working electrically, but its calling up some function that is somehow corrupt. I think the 'personality' of the generic unit is held in an EPROM (the only socketed IC) which knows how many channels are used and whether its for a lathe or mill etc.

Nick, thanks for reminding me about Goodwin, I will call them and see if they are open.

Ian P

Ian

Is it the button HA that blanks the display? I can't lay my hands on the instructions at the moment but I'm not sure that you do have a fault. I have had my unit for at least 5 years and I seem to remember issues with not saving data. The solution that works for me is to use the HA button to put it to sleep and leave power on. I'm sure I got this out of the instruction manual. If I get chance I will see if I can find it.

Regards.

David.

Hi Ian,
If Davids theory is not correct then I suspect the keyboard buttons are on an X Y matirix with the X axis being driven by sequential pulses from the controller chip either directly or via a decoder chip. The Y axis will go to a number of input pins on the controller chip. (X and Y may be transposed from my description.) I would try confirming that there is no short between any row or columns of the matrix by confirming that on the driven axis only one line is active at any time. Also confirm that when the suspect button is pressed only one of the inputs sees a pulse and the pulse is only one time slot of the drive signals. I think it is unlikely to be corrupt software in the controller chip.

Les.

David

So I am not alone!, it is the HA button.

Leaving the power on overnight would be no problem but at the moment, even after reading the manual, I don't seem to be able (for example) select a new encoder resolution and then store it. Whilst in self check pressing the decimal point button shows the first channel encoder resolution, if I change the value and press enter nothing seems to happen, I can step through all the other settings (with the down arrow) but the enter key does nothing.

The channel readings are saved though even if its unplugged for weeks.

In some ways I am not certain there is a fault, it might just be that I cannot understand the manual.

Ian P

Les

I'm certain the keypad is an X-Y matrix. I dont think there are any shorts though, all the buttons work electrically and pressing any one of them is shown by a momentary dimming of the display.

I've heard of stored programme memory getting corrupted but I dont think I have ever seen an example myself so I agree its not likely to be the problem.

Ian P

It happens, believe me! It's why I never use PIC microcontrollers.

Andrew

Neil

On the radio in one of my vehicles its possible to select whether the radio turns on at the last used setting, or at a preset level. Maybe you inadvertently changed the setting.

Ian P

Try calling Colin at CBR electronics 07761649229 he's very knowledgable and sell SINO dro's on Ebay as 3977Colin. Nice guy, very knowldeagle, no connection other than satisifed customer.

After another read of the manual I now know the button that blanks the display is actually doing what it supposed to do! Everything seems to work other except I cannot save the setup values.

The user manual cover six versions of this model, it appears to be the correct one but its badly written I am beginning to wonder if I have missed something obvious.

David (Colwill) is your unit a SDS 2-2L? If so what is the title of the manual you have (All I have is a file 'SDS2_eng.pdf''. I would be interested to know if you can save the encoder resolution and direction parameters and what buttons you press to make it store them.

Ian P

Hi Ian

Yes mine is an SDS 2-2L. The manual that I have is a Machine DRO manual which covers the lathe and milling machine versions. I have taken photos of the manual (lathe bits only) and will try and post them as an album.

Regards.

David.

Hi Ian,

All done. Let me know if there is any of it that's unreadable and I will enlarge the relevant bits.

Regards.

David.

.

Is there a removable back up battery on the circuit board.?

If so remove the unit from the mains supply, remove the back up battery for a couple of mins. Replace battery (pref with a new one) - This will force a 'hard reset' of the system.

I have on many occasions found this to work on electronic systems when the backup battery is getting low the equipment can work in parts but does all kind of strange things. Digital cameras being one example. I am sure many have been thrown away when the have stopped working because the owners did not realise there was another small battery hidden behind a screwed cover.

Just a thought.!

Nick

David

The manual I have is fully legible but its the text that confuses me.

In one of my albums (DRO) is a photo of the unit I have, it does almost match the picture in the manual and I think the only difference is the little indicator below the Y window is not present on mine. (X window does has the 'Rad' though)

On power up pressing the DP key put the unit in setup mode. I can enter numbers to change the encoder resolution, the manual then says to press 'enter' then the down arrow (to move to the next axis). On my unit pressing the enter key does not seem to do anything so even if I go through all the settings they always stick to the old values.

Please could you see if the instructions in your manual say anything different than the one I have?

Thanks

Ian P

Nick

There is no battery backup, data is stored in an EEPROM and its working OK for all other settings and values. Problem is that by following the user instructions I cannot get the enter key to 'write' the data.

Ia P

It works!!!

I just spoke to (I think Darren) of Goodwin Technology. I rang a mobile number and when I described the problem he was driving but then parked in a layby and we had a short chat. I followed his verbal instructions pressing the buttons and feeding back the displayed results.

Contrary to what is shown in my manual, after putting in a new value, the DP key has to be pressed! (manual show the enter key only)

So Darren on behalf of Goodwin Technology kindly and courteously solved the problem and as a bonus wished me happy Christmas too, which is an example of excellent customer service, and I'm not even a customer!

The scales I ordered are due for delivery in the next hour so should have it all up and running by teatime.

Thanks for all the replies here too.

Ian P

I have been a customer of Goodwin Technology for a lathe, milling machine and also DRO systems for both.

Considering we seem quick to complain about services received etc I thought I would be quick to compliment on the superb sales and after sales service I have received by Goodwin technology.

Darren is more than helpful and quite happy to give advice.

I have no connection with Goodwin other than a highly satisfied customer of the items above and would not hesitate to recommend them to anybody.

Happy machining to all

Dave