Pioneer QD-240 CD4 Demod:

Hello,this is my first post and I trust someone here can give me some info on my Pioneer QD-240 demodulator.I've been able to download the schematics for the 240 but I can not find the user manual.Does anyone here know where I might find the user manual? I have set this up on my sound system and I like what I hear.I have the manuals for everything I own with my setup and I would like to have this manual for my QD-240.Thanks for any info,Lawrence.

Hi there mietecch55 and welcome. I am surprised no one here could help with your manual quest. I have acquired one of these as well and am confused how to set it up. So if any QQ's has the owner's manual and can share via pdf or upload it to quadraphonic.info for all to share, there is two of us that would be grateful. Thanks in advance,
Matthew

Ditto that request. For both the 210 AND 240. I made a similar one elsewhere here. The basics are intuitive, but the manuals should be online. And aren't. That hurts the value of the pieces themselves. What might be accrued from one sale is lost on the value of the decoders themselves over time. Better to post it to one of the audio sites. (Like this one, if it's possible to do so.) If not, then on some of the Yahoo group websites or AK.

I have the original manual, warranty card and foldout schematic. I can scan the manual and warranty card (not the schematic, it is too large) and post them hear or if you send me a self addressed paid envelope, I will send the originals to you. We can work out how to exchange addresses. I no longer need the documents since my QD-240 rolled craps. So I took a CD4 demo from a scraped Fisher 634 receiver and put it in the QD-240 chassis, added the necessary Power Supply Mods and low and behold I have A cd4-392 Based Stand Alone Demod.

You can see it at the link: https://www.quadraphonicquad.com/fo...ot-Bride-of-Frankenstein-quot-CD4-Demodulator. If the postimg link don't work, let me know.

Later

I would be very grateful to have the originals. If you have a paypal account, I will send you what you think fair for the time, trouble and expense to send them. If not we'll work something else out that's best for you. My pdf copy of the SM lacks the resolution to read some of the fine details (voltages, etc.) so the schematic would be a GREAT help. What I really need to do is just hook up a signal generator and send the carrier frequency through the inputs and see if I can get that meter up off the floor. Haven't gotten around to it yet though.....Please tell me how you'd prefer to do this. And I'll try to monitor this thread more closely. The pics looked GREAT, btw.

P.S. I've lost the instructions on how to (return the favor) like member's posts. It's not that I haven't wanted to like MANY of them, I'm just inured in the FB tradition of not having to look far to find it. I can't find the widget that posts a like yet. Any help's appreciated......

Thanks for looking at the Pics and a positive comment on them.

Now to answer to the best of my limited ability a couple of questions you had. 1st off I am no expert on forum navigation, but I think that you 1st need to be logged in and then under the post that you would like to "like" there is a thumbs-up symbol that all you have to do is press.

2nd, now concerning using test signals from a generator to check out a CD4 demod, I have found out that there is not much I could do. All I could do is check the capture level of the 30KHZ signal and if the Demod locked onto the signal and that the CD4 radar light lit up. To truly check the deflection of the meter you have to have a very precise signal going in. For both the right and left you would need to generate a Front + Rear main signal and a 30KHZ signal modulated with a Front - Rear signal. You would have to apply a reverse ARNS curve to the Front - Rear signal and a reverse RIAA curve to the Front + Rear. Basically you would need to have a makeshift Meguro-321 generator. This is beyond what I can do now, so I just use the common test record.

Thanks for followup. Some posts only have an option to "blog" them. Odd. In this thread yours was the only one with a like button. It's a bit of a whiskey-tango-foxtrot, but I won't lose sleep over it if nobody else does.

Quad test records I have in spades. (Including one with a very quirky version of 25 or 6 to 4 on it.) No cartridge (including a formerly affordable AT-150mlx) produces a result. But Winter's coming and what seems to be not worthwhile in August can see its curiosity satisfaction co-efficient go up in January....lol.....

I'd like to take a minute to thank jwb474 for his kind assistance with regard to supplying me with ORIGINAL QD-240 manuals and schematics. I went from 0-60 in getting original copies of both (and an original SM) after over a year or searching and scrounging. He also VERY generously offered some extra QD-240 circuit boards/potentiometer to aid my attempt to resuscitate my own QD-240. He pointed out some Matrixing/Phase issues that I hadn't taken into consideration, so I'm now aware that this is going to be a "growth opportunity" for my knowledge level. My formal electronics training was done in the late '80's and that was only for a year, so I'm in new territory. I appreciate both his and the group's contributions to my project and I will post back as progress is made. Thanks again, jwb......you are a CLASS act, sir.

It is my pleasure to help when I can. The quest to do CD4 is a challenging one. The 4DD-5 is a very good piece. At lot of design commonalty is shared the the CD4-10 and the CD4-10 Studio is considered a statement piece. There is posted on this forum a Mod instruction to bring the 4DD-5 (And Marantz CD 400 ,not the 400B) up to a level getting closer to the CD4-10. The next items are to get a good CD4 phono cartridge, plenty of info hear on the forums to do that and a turntable with low capacitance cabling. The last thing you need is a cabling system that attenuates the up to 50KHZ signal from the phono cartridge. This is especially true when using a cartridge that is not CD4 rated as it's signal will be dropping more in level as it approaches 50Khz.
My quest for the ultimate CD4 experience can be examined by going to the "Quadraphonic Hardware- Vintage Equipment Repairs and Modifications and look at my ongoing projects labeled "Frankenstein CD4 Demodulator, Bride of Frankenstein CD4 Demodulator and CD4-10 Studio Mod project. Keep us updated on your progress.

I missed this thread previously, but I have access to large format scanners (up to 36" wide sheets) at work if there are any unavailable online large format schematics that need to be scanned. You *could* take them to a professional service but that wouldn't be cheap...

I probably couldn't get away with doing large batches, but a few here and there for rare gear, no problem.

Hi, does anybody has got the owner's manual & service manual for this unit?

Hi, does somebody has got a copy of the owner's manual and/or service for the pioneer QD-240? could he or she upload it on QQ forum as it is as rare as hens teeth (couldn't locate anything on the web)

Quadly McQuadmeister said:

I'd like to take a minute to thank jwb474 for his kind assistance with regard to supplying me with ORIGINAL QD-240 manuals and schematics. I went from 0-60 in getting original copies of both (and an original SM) after over a year or searching and scrounging. He also VERY generously offered some extra QD-240 circuit boards/potentiometer to aid my attempt to resuscitate my own QD-240. He pointed out some Matrixing/Phase issues that I hadn't taken into consideration, so I'm now aware that this is going to be a "growth opportunity" for my knowledge level. My formal electronics training was done in the late '80's and that was only for a year, so I'm in new territory. I appreciate both his and the group's contributions to my project and I will post back as progress is made. Thanks again, jwb......you are a CLASS act, sir.

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Do you still have the instruction manual for the QD-240 I've tried to find one on the web, to no avail! it's impossible to find. a copy as PDF file would be much appreciated if you can spare the time
Thanks