SPC900 LXmod yesyes style ;-)

[datman]

I did this mod a liitle while ago, using the instructions and schmatic provided by YesYes. Off all the guides, I found this the easiest to understand.

I also had great difficulty with Q3. You'll need a very fine soldering tip and a steady hand. Took me a few goes, I was 64-65 at the time.

The ccd board has another board mounted on top of it with a soldered plug/socket connecting both together.

The gap between is not very big and I'd say fitting a peltier wasn't much of an option.

Although this socket connection could be extended I've no idea how it would affect the function of the camera. Signal timing made be critical.

It may not work at all.

If you just want this for planetary imaging there are now a number of relatively cheap ccd cameras available.

If you want to use it for very long DSO exposures I'd say don't bother get a DSLR or a dedicated Astro ccd.

[Leo.A]

I hope you bought the right size. They are smaller than the standard 0.1" / 2.54mm pitch.

Yes, 2mm pitch for the 20 pin header joining the 2 boards and 1.27mm for the USB header.

I'm aware of the need for the heat sink on the peltier but depending on the temp I want to run (supplied voltage regulated) I have played quite a lot with a couple without fan.

Although this socket connection could be extended I've no idea how it would affect the function of the camera. Signal timing made be critical.

That's the one thing I was concerned about.

I don't really have the disposable income to purchase a dedicated CCD and my DSLR is an old 10.2MP Nikon D80 which seems to suffer considerably from amp glow.

I've spent around $40 on components to do the mod and if it doesn't work, it will be back to the drawing board (and my modded xBox 360 cam)

I'm still in the planning phase while awaiting delivery of my components and anything/everything can change. As long as my SPC880 still works for planetry imaging when I've finished I guess I'll be happy but I'd really like to try DSO's.

Thanks for the replies!

[datman]

OK

Another thought, before you get in too deep, why not just do the mod then try it, as it is.  My main worry when I was doing this mod was "will it ever work again?"

Mine fitted quite comfortably into a 100x75x55mm plastic project box. If you do some seriously complicated mods all in one go and it doesn't work, where did it do wrong?

I'd say almost impossible to fault find.

[Leo.A]

I will be doing it in stages, or more to the point, testing it in stages. Nothing happens too fast around my place with chronic migraines every day.

I'll still do the LX and amp off in one hit, be illogical not to but while the thing is in pieces (OK, boards separated), I'll slip a small heatsink behind the sensor and slap a fan on the case. That in itself may be sufficient but I'm still keen on playing with the coolers since I purchased half a dozen of them. If a fan and heatsink cool sufficiently to reduce noise I'll use the peltiers for some other project.

The mod will be somewaht simplifeid and complicated at the same time by using headers instead of direct solder points. It will make it easier for me to trace my mods and less risk of me damaging anything with a soldering iron. I spent many years studying electronics (diploma level engineering at TAFE)  and have done a lot of soldering but, with bad, blurry vision even magnifiers won't assist, I keep soldering to a minimum.

Next task is my pier mount but that's when the weather clears. At least I have everything I need for that (except a shed to weld in).

[Leo.A]

Sorry to be a pain.

I've seen mention of lines appearing, similar to scan lines on a TV after the mod. If anyone is interested in knowing, the original stand-off's are also earth points along with the little spring connector in one corner. If the stand-off's are not refitted correctly, this is the result. The lines are due to poor earthing.

[michael8554]

I'd be grateful for some help fault-finding on my yesyes modded 900

First, many thanks to YesYes for this compact USB solution

I've just read through all 38 pages of his post and have got useful info from that

In SharpCap it's working in non-LX mode, but not in LX mode.
I get a grey display, the noise pattern changes at the end of each long exposure period.

USB to Serial is recognised in XP as "Prolific USB-to-Serial" on COM2
"Philips SPC900NC PC Camera (LX Mode)" selected in SharpCap
"Exposure Control Line" set to RTS and "Amp Off Control Line" to DTS (inverts are not checked, but makes no difference when checked)
The exposure progress bar at bottom right progresses and the preview frame count rises.

The hi/lo voltage readings below are during exposure, then during readout.
The readout period is short and my DVM is too slow to register the real reading, so I will report the lowest seen.

At the RTS diode anode I get 4.7v, then down to below 2v
At the first BC547 base 0.675v, then 0.2v
At the first BC547 collector/second BC547 base it's inverted, 0v then 3.3v
At second BC547 collector (Base 9) it's 3.8v, then 3.3v - these two are accurate readings, the range seems rather small?
Second BC547 emitter (Pin 9) is steady at 3.23v

Some have reported that with the LX switch left open the camera works in both modes, but mine has to have the switch closed for non-LX to work.
Also the exposure settings in SharpCap seem wrong eg an 18sec exposure takes about 12secs, judging by the progress bar and DVM readings.

Can anyone please supply the correct BC547 voltages?

The circuit is here:

http://www.yesyes.info/index.php/download_file/17/84/

Your hopefully

Michael

[deanc]

michael8554,

Had the same problem before, but found out I messed with the DB9 connector pinout and counted backwards. I noticed this when I poked around with my DVM and found out that what I assumed pin 5 was not in anyways connected with circuit ground, it was actually pin 1 on the DB9. Also during this time the cathode of the zener diode was fixed at 15V wherein it should have dropped to 11V when active.

hope this helps.....

[deanc]

Here's my yesyes style mod.  Managed to fit everything inside the original case, amazing what mototool  can do

[Ellery]

I wanted to try this mod and ordered all the various bits, but it seems I bought the wrong serial to usb adapter, it has the same prolifc chip but only 5 pins on the serial side, 3.3v, 5v,gnd, txd and rxd instead of the usual 9 so I'm missing the rts and dtr lines used in this mod. Can I still use it if I solder the rts and dtr wires directly on the chip? 

 

   This is the adapter I have, it's one sided and with only 5 pins.

  And the schematic of the chipset itself from Prolific's website, among its legs are the 2 lines the board doesn't have pins for, rts and dtr

 

 

[roblegion]

Can you please post a diagram of the original schematic, (I don't want to trawl back through 31 pages) and are the last two photos of what you have, or what you need?

I will help as much as I can.

[yesyes]

The schematic is here:

http://www.yesyes.info/index.php/how-tos/modding-an-spc880-900-webcam-for-long-exposure/

It should work with that adapter if the RTS and DTR lines act as they should. If you have that adapter already, then it's worth trying.

And since it is a TTL level adapter you don't need the diodes (they are there to block the negative voltages of an RS232 levels adapter). Just connect RTS and DTR straight to the 10k resistors.

[Ellery]

Thanks Rob and Chris, yes I have the adapter already unfortunately (and the diodes too). Just to be sure before I touch anything, the correct way to use this adapter version would be to solder it like in this image, just on the 2nd and 3rd pins on the left?

[yesyes]

That looks about right...

What is the capacitor for?

[Ellery]

I wouldn't know ^^ I picked the image through google and I think it belonged to a russian forum.

I did try soldering but it was hopeless with my big tip and in a couple of minutes I could see the first pins connected together by tin residues, I will order the right adapter version next week and have another try.

[roblegion]

Hi Chris (yesyes) , still following this, but (rightly or or wrongly), started a thread as to whether it is still worth the effort, (please give a clue in my new thread) as you are the SPC900 god, would love to hear your views.

The ccd chips are good, we know that, do i need something better for guiding, or something better for imaging?. Or something better for both.

If I had £100 budget for a camera (1 Camera) (tops) should I be spending it on  getting these bad boys to do what I want, or stick 'em on ebay and put it toward something else?

 

 

[yesyes]

Hi Rob. I have replied in the other thread.

[pete98]

Having never completed my PCV675 mod, I just had to do this mod for piece of mind.  With all the talk about the bad usb-serial adaptors being sold, I decided to get mine direct from Sabrent. 

I'm going to guess they changed the way they made the molded plastic on the ones being sold now.  It's almost a "hot-dip"  Very difficult to cut away from the board.  And to make things worse, they changed that capacitor (the CC30PB in the OP pictures) from a board mounted cap to one with 2 very thin leads.  I broke one lead off at the base of the cap getting the enclosure off.  Not enough to solder too, but think I succesfully super glued the wire back on.  The computer recoginzes the device, but guess I won't know till the rest of the mod is done.

Funny, as soon as I noticed  I broke the lead, I went on ebay and got another cheap adaptor.  Do belive I got the same one pictured by Nebula.  Never noticed there were only 5 leads on the serial side, but damn it looked so easy to break away the clear plastic case.

[pete98]

For what it may be worth to anyone, this serial adaptor does have all the serial pins, and worked fine (under xp)

search ebay for: High Speed USB 2.0 To RS232 PL2303 Double Chipset Serial Convert Adapter HR

very soft plastic case, cut away very easy.  Less than 2 dollars vs 9.00 for the Sabrent adaptor.

 

[JimFR]

On 09/10/2014 at 10:01, deanc said:

Here's my yesyes style mod.  Managed to fit everything inside the original case, amazing what mototool  can do

I was considering the mod too, but want to keep the original case, so may do the 'dead bug' instead but your picture gives me hope!

I looked at fans like that in Maplin t'other day - how are your results with this one?