The [URL="https://www.alldatasheet.com/datasheet-pdf/view/108398/ETC/STK4191II.html"]datasheet[/URL] for the STK4191 would be a good reference. Does the left fuse connect to any of the pins on the STK4191?The [URL="https://www.alldatasheet.com/datasheet-pdf/view/108398/ETC/STK4191II.html"]datasheet[/URL] for the STK4191 would be a good reference. Does the left fuse connect to any of the pins on the STK4191?The [URL="https://www.alldatasheet.com/datasheet-pdf/view/108398/ETC/STK4191II.html"]datasheet[/URL] for the STK4191 would be a good reference. Does the left fuse

I put in a new super cap and the settings now save for much longer, lasted overnight.

In usage, the settings don't last long without being in standby. I was thinking the super capacitor should be replaced. The schematic and parts lists seems to differ in capacity. it seems like the higher the farads the longer the settings will be retained. R7079 should limit the charge current?

[ATTACH=JSON]{"data-align":"none","data-size":"small","data-attachmentid":3253330}[/ATTACH] [ATTACH=JSON]{"data-align":"none","data-size":"small","data-attachmentid":3253331}[/ATTACH]
The...

That seems to have been a bad solder joint as well. The remote is working again.

If everything holds, the final repair tally was one muting resistor and one remote sensor....

It seems it was a poor connection. I re-flowed from FMUT to the diode D3182, transistor Q3185, the jumper wires to the mute transistor inputs and all seems well with protect.

The bad news is the remote sensing has mostly stopped working....

Dang it, I'm still getting a protect on power up sometimes. FMUT is 2V on power up and goes to 0V after enabling the speaker relay. The base on the muting transistors is not changing so I suspect Q3185.

The IR sensor was bad. Nothing on the signal line when receiving an IR signal. I swapped in another sensor from a scrap receiver and now it's working....

You would really only need 4 channels if you want to look at all signals at the same time to decode the chip operations. Verify whether each signal toggles individually first.

If the clock speed is low enough you can use a [URL="https://www.temu.com/ul/kuiper/un9.html?subj=goods-un&_bg_fs=1&_p_jump_id=894&_x_vst_scene=adg&goods_id=601099539676607&sku_id=17592313532396&adg_ctx=a-dd26d8e5~c-dd8bfb8a~f-149302f9&_x_ads_sub_channel=shopping&_p_rfs=1&_x_ns_prz_type=-1&_x_ns_sku_id=17592313532396&mrk_rec=1&_x_ads_channel=google&_x_gmc_account=647900107&_x_login_type=Google&_x_ads_account=1919904652&_x_ads_set=21019380395&_x_ads_id=159035039019&_x_ads_creative_id=690830436449&_x_ns_source=g&_x_ns_gclid=Cj0KCQjw2uiwBhCXARIsACMvIU1z7meFMPATJrgtKWq7ByqrjNF0rNECcYJnaLSjas1B_g871dijRRQaApVlEALw_wcB&_x_ns_placement=&_x_ns_match_type=&_x_ns_ad_position=&_x_ns_product_id=17592313532396&_x_ns_target=&_x_ns_devicemodel=&_x_ns_wbraid=Cj4KCAjwt-OwBhAqEi4AM9Mc201UDBYDYxaXmOzqtyixEmVvByMOw0lAa5kyQT6zUiNHL37oDTEdezFHGgLHiQ&_x_ns_gbraid=0AAAAAo4mICGXucJzRCZeh0-5Shsg0OBQv&_x_ns_targetid=pla-2310464807724&gad_source=1&gclid=Cj0KCQjw2uiwBhCXARIsACMvIU1z7meFMPATJrgtKWq7ByqrjNF0rNECcYJnaLSjas1B_g871dijRRQaApVlEALw_wcB"]cheap...

Heh, I thought I was out of the woods but the remote does not work. It's not the remote as it works with another receiver. Back to the schematic.

Thank you [USER="29541"]redwire[/USER] for your help. I got the part in the mail today and replaced it and everything is working perfectly. Now I have 9 extra RN1241s. Q3383 has been replaced and no more protect shut offs or popping from Speaker B.redwireThank you [USER="29541"]redwire[/USER] for your help. I got the part

I would assume you mean "No ROM Connection"?

When /CS is low the EEPROM should be accepting data from pin 95. It's likely commands to set the address to read from but could also be an address to write to as well.

You could verify that the four SPI signals are toggling. If everything toggles except for SO then the EEPROM is not working. CLK, CS and SI are driven by the DSP. The EEPROM toggles SO....

It's a SPI EEPROM. A SPI bus uses 4 signals, clock (SCK from DSP), chip select (/CS from DSP), data in (SI or slave in from DSP) and data out (SO or slave out to DSP). When CS is asserted (low) the EEPROM will accept data on SI every clock cycle (SCK) and potentially output data on SO every clock cycle. WP is write protect.

I pulled Q3383 completely and there is no more popping from enabling/disabling the B speakers. My theory is that this is also the source of the changing input protection since it will mute during change and then pop from ground to -2V.

The only unexpected behavior (to me anyway) now is that the protect is always being asserted on power up from the surround/remote amp board.

I ordered the part and it will be here next week.

I think I found a problem responsible for the B speaker popping. It's only on the left channel. What's happening is when enabling the B speakers, I believe the output of Q3383 is sitting at -2.0V. So the output of Q3181 gradually drifts down to -2.0V. Then when disabling the B speaker, it pops back up to around 0V.

I measured the output of Q3483 to compare and it's sitting at 0V.

This is on NCVD-6566. I disconnected P601 so it's not connected to anything.

It also includes the relay controls.


It's in the switch array in NADIS-6576. 3rd row, 3rd column.


I think it does activate MUTE while switching B on or off. I am suspecting either MUTE or whatever switches between surround and remote speaker input signals. I will look at this tonight....

I'm guessing FMUT to NCVD-6566 is where I should be looking.

I've got some data that I don't understand. I disconnected JL501B (+24V, I-PRO, V-PRO, REM_EN, GND and SUR_EN) from the surround/remote amp board hoping to isolate the source of the protect between the two amplifier boards, and it half worked. The protect is no longer being triggered by switching between inputs (DVD, VIDEO 1, 2, etc). But it still is being triggered by toggling Speaker B on and off (mostly off).

What could be causing the A speakers to pop (and trigger protect) just by toggling the B speakers?

Switching inputs does not make any noticeable sound on the FR and FL speakers. All inputs tested. Only the FR and FL speakers are connected for all tests (A speakers).

The only popping on the FR and FL speakers is heard when the A speakers are enabled and the B speakers are turned on or off. The pop when turning on the B speakers is not a lot. The pop when turning off the B speakers sounds like something you would want to avoid.

If I turn the A speakers off and on, the speakers do not pop. If I turn the A speakers off, then turn the B speaker on and then off, then turn...