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-   -   Brionvega CUBO Philips / TDA8842 (https://www.vintage-radio.net/forum/showthread.php?t=158550)

obsoletemachine 1st Aug 2019 4:57 pm

Brionvega CUBO Philips / TDA8842
 
hi,
is anyone familiar with the TDA8842 or the Brionvega CUBO? I want to add NTSC to the circuit. I have tried to apply a 3.57mhz xtal to the 35 pin but to no avail.

Maarten 1st Aug 2019 6:22 pm

Re: Brionvega CUBO Philips / TDA8842
 
I'm pretty sure you need to configure the IC to do NTSC. If you're lucky, your set has option bytes that can be set through a service menu.

kan_turk 1st Aug 2019 6:57 pm

Re: Brionvega CUBO Philips / TDA8842
 
Hi
It looks from the data sheet that the 3.58MHz crystal needs to be connected to pin 34 for NTSC but the chip also needs to be programmed accordingly - it is I2C controlled

Necessary programming (firmware) may already be included in the TV but I can’t confirm this as I’m not familiar with that particular model so my comments are of a general nature

Rgds
John

obsoletemachine 3rd Aug 2019 3:51 pm

Re: Brionvega CUBO Philips / TDA8842
 
aH!
There was a chap on here, now banned, who uploaded the contents of the EPROM.

https://www.vintage-radio.net/forum/...=112433&page=2

Datasheet states:

table 10:

XA XB CRYSTAL
0 0 two 3.6 MHz
0 1 one 3.6 MHz (pin 34)
1 0 one 4.4 MHz (pin 35)
1 1 3.6 MHz (pin 34) and 4.4 MHz
(pin 35)

So i need XA and XB to be 1 1

Maarten 4th Aug 2019 2:30 am

Re: Brionvega CUBO Philips / TDA8842
 
Unfortunately, that doesn't translate to EEPROM bytes as XA and XB are set by the processor.

The microcontroller used might be the SAA5553. If you're very lucky, it ill have some kind of variation on the standard programming. Maybe some configuration methods (setting of options bytes, service menu) can be found under CTV832M. Otherwise it would be unique to the Brionvega Cubo or Formenti BV1 chassis so you would need to obtain a service manual.

Other slightly newer Formenti chassis using the UOC (successor to the SAA5553/TDA8842 combo) indeed have option bytes to set systems. In those, the service menu is accessible by pressing OSD on the set, immediately followed by standby on the remote.


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