RCA EEPROM addresses

I disconnected the base drive to the transistor that mutes the audio. Works fine, just a slight pop when you turn the power on or off but no big deal.

But I wouild like to know the answer to your question as well.

Mark

Google this group for the procedure to turn the speakers back on, easy to do.

I have replaced several blown speakers, especially in the 175 series, where someone prior tech bypassed the mute circuit and the constant pop blew it out. I would recommend against the hack approach.

David

Le> Has anyone mapped the addresses in RCA TV EEPROMS to the service

parameters?

I do

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ordering.

find

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like

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There is a very easy way to allow the menu to turn the speakers back on for any technician. The mute line to the audio outputs is there to prevent the dc surge as the power supply comes up from getting to the speakers. Do not forget that these sets have something like a 1 watt speaker in them. David

David,

I am familiar with the procedure you mentioned and did a search of the archives and the FAQ, as I mentioned. I would still like to know the mapping of the addresses to be able to extract service parameters and do the correction to the mute address. If I have to desolder one pin I might as well pull it and read/archive the data from the EEPROM. I am getting a pretty good collection of EEPROM data that has proved useful for testing. The question of what parameters are where in the hex addresses is still an open one. Occasionally I get a dead set that I can still extract data from the EEPROM and the tuning parameters would be nice to pull. Most dead ones, of course, are impossible to get any data from.

BTW, I think disabling the mute circuit in hardware is a half-assed patch. I had one come in with a bad speaker like this as well, and discovered after I replaced the speaker that the resistor had been pulled. These speakers go out without the transients all the time. Why take the chance when the right fix is so easy and cheap?

Leonard

Just for the heck of it for my own info on the =93popping=94 issue, here=92s a couple stats. Normal sound vs. (modified) Set turn on mvdc readings 507 (598) falling to 13 (-61) average 52 (48) duration 1.2 sec (1.5) Set turn off mvdc readings =96451 (-1224) rising to =9635 (476) average =96268 (-97) duration .3 sec (.7) Set turn on mvac readings 273 (294) falling to 20 (32) average 84 (108) duration .9 sec (.9) Set turn off mvac readings 301 (1065) falling to 16 (17) average 86 (224) duration 1.2 sec (1.2) No difference in any readings during normal viewing, changing channels, ect. So going by the readings there is a noticeable difference, and definitely more pop will be heard if the circuit is modified, mostly at turn off, so my opologies, definately a pop issue

Meant to mension the readings were simply across the speaker itself, and don't know where the ? symbols came from. sorry.

On Sat, 16 Apr 2005 06:26:01 -0400, "Leonard Caillouet" put finger to keyboard and composed:

IMO any TV design that cannot bootstrap itself from a blank EEPROM is extremely shoddy. I recommend that the designer be beaten about the head with a blunt instrument. Is it asking too much for a programmer to have seeded the uC's ROM with a basic working configuration which could be automatically downloaded into the EEPROM in the event of a checksum error? Apparently so.

Anyway, it surprises me that nobody (?) has taken the trouble to map out the EEPROM addresses. It would seem to me that the most logical way to uncover the locations of the various functions is to socket the EEPROM and dump its contents after each parameter change.

I'm curious about this turn of phrase. It begs the question, is there a full-arsed anything? ;-)

- Franc Zabkar

my set does not have the mute featutre avaialbe for the user

I have had the the mute signal disconnected for a few years, the set does pop on turn on and off but nothing bad enough to damage a speaker and the speakers seem fine after several years.

But if there is an easy way to get into a menu and turn the mute off so i can reconnect the mute signal, I would like to know that.

Please let me know where I can find this.

thanks

Mark

the

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from

ones,

patch.

Frank,

Thomson is half-arsed, Philips is full-arsed.

Leonard