Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Stereo MPX Decoder for old Sony
#16

I was thinking the same. There are many +12 Ground to -12 polarity converters in the market (mainly for old cars) but not one like that. I would even take +12 to-12 converter.

I thought this Sanyo chip is probably not necessarily positive ground. I can see the legs where the L and R channels are coming out. I can bypass the headphone amp they have built in. But what can I use for a ground? Would the chip's negative supply be the new negative ground. I got stuck there.

In a Yamaha receiver, the same chip is used with a negative ground. I have schematic for it but could not find one for the Sanyo.
#17

Hello Toptip,
First all what is the IC part no . and what is the sony model number ?

Sincerely Richard
#18

The chip is Sanyo A3311. It is obsolete, I could not find a data sheet for it. All my information is from a Yamaha CR500 receiver where it was also used.

The Sony? If you mean Sanyo, it is called RB9000. There are two versions of it, with and without a headphone permanently attached.
#19

Toptip,
Because Sanyo did make a LA 3361 because most sanyo IC chips had LA I used to be a factory Warranty and service for Sanyo/Fisher .

Sincerely Richard
#20

Yes, in fact when I was searching for the A3311, I came across LA3361. It looked quite different. I will send you the schematic of this chip from the Yamaha manual.
#21

Is there a way to load an image?
#22

And you are right. While chip says A3311 on it, elsewhere it does come up as LA3311:

https://icompplus.com/en/others/LA3311
#23

Hi,

This is the schematic showing the chip (which I highlighted in yellow, as I found it confusing).

Is this chip made for a positive ground or is that how Sanyo has used it? 

If possible, I would like to change it to negative ground.

All the best


Attached Files Image(s)
   
#24

The quick answer is "not possible". The VCC to the circuit is negative voltage, the filter caps positives are connected to gnd and the transistors are NPN.
#25

This is the same chip, used with negative ground. I suppose I could do enough surgery to change things from positive to negative but might be easier to build a new circuitboard. I wish I could find the original datasheet with a simple schematic.


Attached Files Image(s)
   




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
1949 Motorola 5A9M
Hello Bob, What nice looking set it looks like a Emerson that I have you did great job with the two Electrolytic cans ....radiorich — 02:04 AM
New find. 91X code 225
Hello Paul, Well, done it looks great ! Sincerely Richardradiorich — 01:55 AM
New find. 91X code 225
Congratulations, Paul! That was quick...you made short order of that chassis restoration! And no coils to rewind...bonus...NostalgiaRadioTime — 01:07 AM
1949 Motorola 5A9M
Bob; I was thinking the same with that 150 ohm resistor, put a larger value replacement in it's place to compensate f...Arran — 01:02 AM
New find. 91X code 225
And the chassis is all done, all caps and bad lamp wiring replaced, power switch repaired and in place, dial string tune...pdieten — 12:37 AM
1949 Motorola 5A9M
As I think more about that 150 ohm resistor that directly follows the selenium diode, I’m going to have to add some seri...klondike98 — 11:47 PM
1949 Motorola 5A9M
It looks like all the resistors except one are OK. Arran mentioned replacing the sand 150 ohm resistor and mine looks l...klondike98 — 02:25 PM
New find. 91X code 225
Yeah the 121/221 documentation was correct for the RF end of the radio. It left me scratching my head when I was looking...pdieten — 11:59 AM
philco predicta
Hi CGL, Yes, troubleshoot the 140V Power supply, something is definitely loading it down, and since this supply excl...MrFixr55 — 07:32 AM
1934 American Bosch 440T restore on YouTube
Looking forward to Part 2.Jimradio — 07:30 AM

[-]
Who's Online
There are currently no members online.

>