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Hilda Winkler <hildawinkler77@gmail.com>: Dec 07 06:03PM -0800 Hi Group, need help choosing a main board for an RCA TV model .. led32c45rq.. main board # fre01m3393lna35-a2.. i want to know if this board ..42RE01M3393LNA35-A2 Main Board for LED42C45RQ will work in replace of the one mentioned ???

"ohg...@gmail.com" <ohger1s@gmail.com>: Dec 08 04:50AM -0800 > Hi Group, need help choosing a main board for an RCA TV model .. led32c45rq.. main board # fre01m3393lna35-a2.. i want to know if this board ..42RE01M3393LNA35-A2 Main Board for LED42C45RQ will work in replace of the one mentioned ???   The only way is to try it. There are two potential problems of high probability: the keyboard switches may not work as assigned, and you may have no picture, a badly pixelated picture, or an upside down picture because these boards don't drive the same screen. If the board is close enough, swapping the eeprom from the original board will usually fix the picture issues and likely the keyboard issues, but that's assuming the original eeprom is good. Since the eeprom is the most likely cause of any non-lightning failures of these boards, you may be moving a bad eeprom into a good board.   I've done that type of swap when I had a board in stock as it only takes a few minutes to try it, but wouldn't order a board for the attempt.   Did you confirm the power supply is OK? Getting standby 5V is not enough. You can jump the stby pin to the ps on pin and see if the 12V comes up. If it doesn't, the power supply is bad. If it does, it's the main.

Trevor Wilson <trevor@rageaudio.com.au>: Dec 08 09:29AM +1100 On 7/12/2020 5:51 am, Peter W. wrote: > My brother has a very vintage pair of Acoustat speakers driven from what he describes to me as an Acoustech IV pre-amp, distinguished by having phono-jack outputs directly to the speakers. Which have large, heavy, powered boxes attached. After many years of sitting unused, they went silent on him. I suspect the pre-amp, but at-a-distance, I cannot be sure. No, I do not have the model number of the speakers, but they are self-powered, very nearly 2 meters tall, just over 6 feet, There are three fuses on the back, a removable power-cord, an on-off switch, the 1/4" phono jack input and a 5-position treble boost/cut knob. Which should narrow it down.   > Question: is that specialized pre-amp required, or would any normal audio pre-amp do?   > Thanks in advance!   **I have some familiarity with a few Acoustat models. I am unaware of any that came with inbuilt power amps, though I guess it is possible that one or two were. I can tell you that the load presented by most Acoustats is brutal. Only amplifiers capable of substantial current ability and unconditional stability should be used. Here is an impedance graph I ran on an old Acoustat amny years ago:   https://www.rageaudio.com.au/index.php?p=1_12   Check out the dip at 15kHz.     -- Trevor Wilson www.rageaudio.com.au   -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

Phil Allison <pallison49@gmail.com>: Dec 07 05:39PM -0800 Trevor Wilson Bullshitted: ======================     > **I have some familiarity with a few Acoustat models. I am unaware of > any that came with inbuilt power amps, though I guess it is possible > that one or two were.   ** The modlel " X " IIRC.   Direct drive form the tubes runnint at 5kV.     I can tell you that the load presented by most > graph I ran on an old Acoustat amny years ago:   > https://www.rageaudio.com.au/index.php?p=1_12   > Check out the dip at 15kHz.   ** Very easy load for any sanely built amp.   Trouble for your nutty MEs - were they ??     ..... Phil

Trevor Wilson <trevor@rageaudio.com.au>: Dec 08 02:38PM +1100 On 8/12/2020 12:39 pm, Phil Allison wrote: >> that one or two were.   > ** The modlel " X " IIRC.   > Direct drive form the tubes runnint at 5kV.   **Fuck me. I think you're correct. Direct drive ESLs - the Holy Grail. Very rare. Never seen one. I've worked on 2+2, 1+1 and Spectra models (the impedance curve was a Spectra).     >> Check out the dip at 15kHz.   > ** Very easy load for any sanely built amp.   > Trouble for your nutty MEs - were they ??   **The ME850, with zero global NFB, a 2.5kVA power transformer, 245,000uF and 70 Amps of continuous (till the mains fuse fails) current capacity? None at all. Perfectly stable, regardless of load. A perfect match for any ESL (or any other speaker, in fact). The ME1400 would do even better, without raising a sweat (5kVA power transformer, 310,000uF and 100 Amps).   Nutty? Maybe, in this era of pretty impressive Class D amps. Still, people like 'em. I know I do.     -- Trevor Wilson www.rageaudio.com.au   -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

Phil Allison <pallison49@gmail.com>: Dec 07 07:46PM -0800 Trevor Wilson wrote: =================   > any ESL (or any other speaker, in fact). The ME1400 would do even > better, without raising a sweat (5kVA power transformer, 310,000uF and > 100 Amps).   ** You omitted the *very real* risk of damaging the input power limiter of a Quad ESL63 and any of its relatives.   But that speaker is not a problem load just because it dips at 15kHz.   ...... Phil

Trevor Wilson <trevor@rageaudio.com.au>: Dec 08 03:20PM +1100 On 8/12/2020 2:46 pm, Phil Allison wrote: >> 100 Amps).   > ** You omitted the *very real* risk of damaging the input power limiter of a Quad ESL63 and any of its relatives.   > But that speaker is not a problem load just because it dips at 15kHz.   **Both amps would certainly fry the TRIAC(?), if pushed. If I recall correctly, the ME850 (maximum output Voltage = 31 VRMS) would not exceed the maximum Voltage limits of the ESL63? The ME1400 certainly would (42 VRMS). Overkill for the ESL63.   Let me know, I'll send one over for you to listen to. I'll cover freight both ways.   FWIW: Musos love the way ME amps deal with transients. Musos seem to be acutely attuned to the way a system delivers transients.     -- Trevor Wilson www.rageaudio.com.au   -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

Phil Allison <pallison49@gmail.com>: Dec 07 09:06PM -0800 Trevor Wilson wrote: ------------------------------- > correctly, the ME850 (maximum output Voltage = 31 VRMS) would not exceed > the maximum Voltage limits of the ESL63? The ME1400 certainly would (42 > VRMS). Overkill for the ESL63.   ** The ESL63 has two input limiting triggers.   1. A voltage peak value of about 35V using a power transistor or zener array.   2. A simple ionisation detector ( uses a 555 ) trips a triac for a short time.   It's often a 1.5ohm, 5W resistor in series with the speaker that can pop. Later marks have a fuse to save it. In any case Quad, warns not to use amps have no VI limiting with their ESLs.     ..... Phil

Trevor Wilson <trevor@rageaudio.com.au>: Dec 08 04:22PM +1100 On 8/12/2020 4:06 pm, Phil Allison wrote:   > It's often a 1.5ohm, 5W resistor in series with the speaker that can pop. > Later marks have a fuse to save it. > In any case Quad, warns not to use amps have no VI limiting with their ESLs.   **An ME550-II then. MUCH more polite. 27 VRMS, 500VA transformer, 120,000uF and 40 Amps of PEAK current. Easier to freight too. Only 16kg. All ME amps are current limited.   Peter Stein learned to his cost, way back in the late 1970s, that pathological speakers loads, like the Infinity RS4.5 would kill a 38 VRMS amp, with around 70 Amps of current ability, but without current limiting. The design genius' at Infinity, decided that it was a good idea to place 2 X 4 Ohm bass drivers in parallel was a good idea. Trouble was, the bass drivers also had a 2 Ohm voice coil, which was paralleled with the 4 Ohm voice coils at LF. The importer smoked several Phase Linear amps, a bunch of Yamahas and several others, before trying the ME. It last 6 weeks, then died horribly. Output stage SOA was exceeded. Peter began fitting current limiters to all subsequent amps.     -- Trevor Wilson www.rageaudio.com.au   -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

Phil Allison <pallison49@gmail.com>: Dec 08 02:59AM -0800 Trevor Wilson wrote: ================= > **An ME550-II then. MUCH more polite. 27 VRMS, 500VA transformer, > 120,000uF and 40 Amps of PEAK current. Easier to freight too. Only 16kg.   > All ME amps are current limited.   ** Really ?   VI limiting is another matter - intended to prevent output stage failure under adverse loads including short circuits. Means the short circuit I max is no more than half the I max into a few ohm resistor - often more like one quarter.       ..... Phil

Tim Schwartz <tim@bristolnj.com>: Dec 07 03:18PM -0500 Hello all,   I'm working on an L-11 which has issues with the -b2 power supply which feeds the front end of both channels of power amp. While I have a good, clear downloaded schematic, it does not have any voltages on it. Any chance that someone here has a factory service manual that you'd be willing to lend, or at least tell me about some of the voltages on the schematic?   Thanks! Tim Schwartz Bristol Electronics

"Peter W." <peterwieck33@gmail.com>: Dec 07 09:00AM -0800 With the understanding that the proper job of the Village Idiot is to make the rest of the villagers look good by contrast, I ask all of you to join me in recognizing the masterful performance of our new incumbent!   Peter Wieck Melrose Park, PA

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