Technics CD-4 Cartridges with no audio output

[Owen Smith]

For trains you get all sorts of strange systems. In and around Germany the trains are on 16 2/3 Hz, because about 100 years ago it was easier to convert DC motors to low frequency AC than standard 50 Hz and a third of 50 Hz was convenient to produce. They're still stuck with it, and still have some dedicated transmission lines for it.

 

[Wurly1]

I believe it was also the case in early fifties in northern part of Quebec
known as Abitibi, the voltage frequency was 50hz.
They decided to replace peoples appliances for new ones and
changed to the standardized 220 /120v 60hz

[/QUOTE]
More precision and a bit of history.
In Abitibi, Quebec, Canada.

In the 50's.
At the behest of Premier Maurice Duplessis, Hydro-Québec acquired Rapide-7 generating station in Abitibi. The utility also undertook development of Rapide-2 on the upper Rivière des Outaouais (Ottawa River). These projects were intended to meet the mining industry's growing power needs. When Hydro-Québec acquired the private electricity distributors in 1963, it became the owner of the region's existing power stations and converted the distribution system frequency from 25 to 60 hertz.

source: Hydro-Quebec.com

 

[RetroQuad]

I wonder why they still have 2 different voltage standards in Japan?
In AU there must be some very annoying light flickering with 25hz.
(it's intriguing to see SANYO parts in a National Panasonic Technics system specially in early 70's)

Japan doesn't have a national grid and different grids were set up by competing companies for different parts of Japan. It's a pity they didn't settle on one standard before commencing construction. And it's 50Hz throughout ALL of Australia.

I notice the label on your turntable motor actually says 50/60Hz 100V. So is there a physical switch somewhere, or is it just compatible with both, and if so does it somehow maintain the correct speed in either situation?

I've been lucky enough to tour the Technics factories twice back in the late 70s and early 80s (a real eye opener!!), and I remember noticing many Sanyo boxes on one of their production lines, containing transistors, and asked our tour host about it. He said it was common for many of the big companies to source components from each other to save having to "tool up" and make them, especially when only relatively small quantities might be needed. I also toured the JVC factories and noticed a huge pile of Sharp boxes on the loading dock ready to ship out. They were VHS-C adaptors made by JVC for Sharp. JVC obviously made the Sharp branded packaging and outer shipping boxes as well.

In 2010 Panasonic acquired Sanyo as a wholly owned subsidiary. The founder of Sanyo (back in 1947), was the brother-in-law of the founder of National Panasonic (Matsushita Electric Co) and also a former employee ... so the company has gone full circle back to where it started from.

 

[Wurly1]

Very interesting informations, thank you RetroQuad.

My motor definitely run faster. There was probably a choice of plater for 50 or 60 hz operation.
Mine clearly show 50Hz.

 

[MidiMagic]

Wrong voltages usually cause the motor to fail to run, run badly, or burn up. The following voltage/frequency combinations are found:

120V 60Hz - Most of North America, southern Japan
100V 50Hz - Northern Japan
240V 25Hz - Parts of Australia
240V 50Hz - Most of the rest of the world


After burning out the motors on an air cleaner and the two replacements Sears sent me, I discovered the motors were 100V 50Hz intended for northern Japan.

I wonder why they still have 2 different voltage standards in Japan?

In AU the're must be some very annoying light flickering with 25hz.

Strange Sears sent you the wrong motor, at least you found out before throwing it out.

They didn't send me two motors, they sent me two more air cleaners. All of them burned up. The spec plate says 100V 50Hz. I got one to work by connecting a light bulb in series with the motor after unseizing the bearings.

And I didn't know about Japan's two power systems until later (which made me understand the problem). I read that in a book I got much later. It also tells how northern Japan's system was made during World War II by German engineers, while the southern one was made by American engineers during occupation after the war. Mountains originally prevented a grid.

The nuclear power plant destroyed by the tsunami was the main source of 50Hz 100V at that time, so they have a shortage of it now. Most dwellings in northern Japan now have 20 or 30 amp services.

At the time an engineering book I have was written in the 1950s, parts of Australia had 25Hz power because the mines that were the main industries in those towns had 25Hz generators. The rest of Australia had 50Hz. I did not realize that all of those were now gone.

 

[Wurly1]

Little update about my SS-1100D (sabotaged) system.
After having found a little wire short-circuiting the left and right channels, i found another anomaly on the SC cartridge bias pcb located under the turntable.
See pic 2. After removing some solder i found this was another short made on purpose by previous owner or tech. See pic 3

 

[Circular Vibes]

Hope you get it restored and working with the SG cart. I love my SG and am getting another preamp as I can not schematics to restore the 3 I already have. They are the only CD4 carts that I actually prefer over my AT440MLB.

 

[Wurly1]

Hope you get it restored and working with the SG cart. I love my SG and am getting another preamp as I can not schematics to restore the 3 I already have. They are the only CD4 carts that I actually prefer over my AT440MLB.

I can't wait to hear it!
I hope my SG cart have not been damaged by this short circuit.
I actually draw the detailed schematics of the SS-1100D amplifier to understand it's working. I learned a lot on this design and for one thing, all audio sources are passing thru the CD-4 board. The decoding is de-activated and a large part of the board is bypassed when sources other than phono are selected. The only thing i haven't draw yet is the CD-4 decoder and tuner section. I will have to draw it if the system still not work after reassembly which in under way.

 

[Circular Vibes]

Are you in a major city? Toronto has the reference library with an extensive schematic collection including most of the Howard Sams manuals available for photocopy in library. Many other resources too if you just ask. Be aware they may be very nosy while you look as some asshat took a razor blade to the entire RCA book collection years ago. Montreal, Vancouver and others may also have similar resources as well as well stocked Uni libraries.

 

[Owen Smith]

I find it hard to reconcile something as low budget looking as an all in one system having something as esoteric as a strain gauge cartridge. Even the concept of an all in one CD-4 system seems strange.

 

[Circular Vibes]

It was common to use the SG carts in all in ones in Japan. I do not know why. They work well and may have been cheaper to produce at the time. There were also conical styli for them very cheap and still widely available. I agree SG have great potential and is a waste on all in one systems of cheaper construction but at least they didn't revert to using ceramics. There was also a different taxation in Japan and Australia (maybe other countries too?) that made all in one cabinet systems more affordable than separates and also attempted to get the new quad into more homes at leas cost. It was a somewhat failed attempt to convert the rest of us to 4 channel. Asmirable but ill fated regrettably.

 

[Wurly1]

Are you in a major city? Toronto has the reference library with an extensive schematic collection including most of the Howard Sams manuals available for photocopy in library.

I'm not in a big city, i'm located in the eastern townships, province of Quebec.
I've been looking all around for schematics. I even wrote a letter translated in japanese to National Panasonic/Technics and they told me the schematics for this model are not availlable due to the fact it's an 1974 model and that they were never published.

 

[Wurly1]

I find it hard to reconcile something as low budget looking as an all in one system having something as esoteric as a strain gauge cartridge. Even the concept of an all in one CD-4 system seems strange.

My work on drawing the schematics helped me understand better why they made all in one systems. Everything's design to be a perfect fit. The strain gauge cartridge does not need a preamp, the RIAA response curve is buit-in. Further: after the input selector there is a wide band power amplifier that boost the audio signal and the carrier before being fed to the CD-4 decoder board.
My conclusion is: All-in-one design was the best way to make sure CD-4 would work flawlesly out of the box.

 

[Owen Smith]

My work on drawing the schematics helped me understand better why they made all in one systems. Everything's design to be a perfect fit. The strain gauge cartridge does not need a preamp, the RIAA response curve is buit-in. Further: after the input selector there is a wide band power amplifier that boost the audio signal and the carrier before being fed to the CD-4 decoder board.
My conclusion is: All-in-one design was the best way to make sure CD-4 would work flawlesly out of the box.

The RIAA response curve being built in to the cartridge is contrary to standard CD-4 practice where the FM rear subcarriers are demodulated before the RIAA equalisation. Does that cause any problems?

 

[Circular Vibes]

The RIAA response curve being built in to the cartridge is contrary to standard CD-4 practice where the FM rear subcarriers are demodulated before the RIAA equalisation. Does that cause any problems?

My experience with SG is always with outboard Japanese demogitators. I can not tell you if it is "accurate or proper" but I can say I very much enjoy the sound and the ease of use is without compare in the CD4 world. I have 3 demogitators to have restored without schematics. Wurly, I have not seen National/Panasonic/Technics schematics from Japan but they were publishing "technical manuals" since the black and white tube TV era. I have seen unrelated ones on Yahoo Auctions. There were also schematics in Japanese magazines called Radio Technology or something like that in Google Translate. I can not find any indices for the mags as they are old and defunct and in Japanese. There were many specific 4 channel editions. If I find out more I will share the info publicly.

 

[Wurly1]

The RIAA response curve being built in to the cartridge is contrary to standard CD-4 practice where the FM rear subcarriers are demodulated before the RIAA equalisation. Does that cause any problems?

It sure is a good idea to demodulate before RIAA curve as the later will decrease high frequency levels and certainly mute the 30khz carrier.
According to the data i have about the EPC-451c cartrige, the output (once properly biased) can be fed directly to an amplifier, no RIAA correction curve needed. (of course the signal is about 3 mv, not line level)
This cartridge is design to provide a stable carrier level and have a frequency response up to 50khz.
I can tell you in the schematics i've made there is no RIAA curve applied unless it's applied later on on the CD-4 board but i don't think so.

Maybe these all-in-one systems where design to avoid culprits found in the standardized world.

 

[gvl_guy]

My work on drawing the schematics helped me understand better why they made all in one systems. Everything's design to be a perfect fit. The strain gauge cartridge does not need a preamp, the RIAA response curve is buit-in. Further: after the input selector there is a wide band power amplifier that boost the audio signal and the carrier before being fed to the CD-4 decoder board.
My conclusion is: All-in-one design was the best way to make sure CD-4 would work flawlesly out of the box.

My first quad, a Panasonic all in one turntable (a BSR, actually) worked flawlessly.

 

[Circular Vibes]

My first quad, a Panasonic all in one turntable (a BSR, actually) worked flawlessly.

That is exactly how I got my first SG cart. There was a dismembered version of that at a local thrift store. Inused my partners 30% seniors discount on $24.95 and ran quickly home. The built in demogitator sucked likely due to failed components. I still have the carcass in the garage but the cart has many hours on my Technics SL 1200. SG is so easy to use that I look forward to getting the demogitators going again.

 

[Wurly1]

My first quad, a Panasonic all in one turntable (a BSR, actually) worked flawlessly.

That's awesome! BSR turntables where workhorses but a bit noisy. The EPC-451c cartridge is not affected by magnetic fields found on cheaper tt 2 poles AC motors and since it's not a magnetic coil, it's not affected by the capacitance of low budget wires and can be seperated from the decoder unit.

So any turntable with a stable and accurate speed would theoratically work.

Souce: Operating instructions, Panasonic EPC-451c found on The Vinyl Engine web site.

 

[Wurly1]

That is exactly how I got my first SG cart. There was a dismembered version of that at a local thrift store. Inused my partners 30% seniors discount on $24.95 and ran quickly home. The built in demogitator sucked likely due to failed components. I still have the carcass in the garage but the cart has many hours on my Technics SL 1200. SG is so easy to use that I look forward to getting the demogitators going again.

I really hope you'll be able to put it back into service.