Denon AVR-3808ci no video, no digital anything

Symptoms

• No video out
• No OSD
• No surround sound

Diagnosis

• Try to determine what all these have in common
• Self-test confirms suspicions
• Check voltages
• Determine area of failure
• Test suspect components
• Pull components that seem suspect for out-of-circuit testing
• Dig for a suitable relacement and test

Link to the service manual here (free, but you need an account. I find this site very useful, but the manual is available elsewhere if you care to look.)

Link to a replacement KSA1281 transistor from Mouser here.

SSF / HP filter mod for Behringer EP2500

If new to the page- start from the top.  If not, scroll down for updates.

3/16/2012
I'm cheap.   And I like home theater and audio.   In my theater room, I am using a Behringer EP2500 amplifier to drive my subwoofer.
I need a subsonic filter to protect my subs from over-excursion at extremely low frequencies.   Behringer includes two switchable 12db/octave (2nd order) high-pass crossovers with the units, but the frequencies (30hz and 50hz) are too high for what I am needing.

I was able to find a schemtic and have identified the opamps and components that set these frequencies.   The opamp is a TI 4580 opamp.   It's IC4 (ch1) and IC6(ch2) on the amp.   This is a dual-channel opamp.   One half is used as the input buffer, the second half is used for the LP filter (or inverting amp for bridging/parallel mode on ch2).

Here is a snippet of the schematic of ch1:




DISCLAIMER:   I am not an electrical engineer.   I do this as a hobby.   At this time this is simply a mental exercise- I have not made these mods and I have only been examining the schematic for about an hour.   These are notes more for me so that when I wake up in the morning, I will be able to remember what I did today.   When I do these mods, I will post back my results.   Please take my info with a grain of salt.

The signal enters the amp board at pins 2&3.   It is buffered at IC4A, DC protected at C15 (HP filtered around 3hz), then sent to the gain pot (VR7A).   From there, the default (50hz HP) signal path is thru R161 and then enters the 50hz HP filter consisting of C27, R169, C26, and R168.   Bypass mode (pins 8&9) bypasses these components and drops the signal directly into the input of IC4B.   30hz mode (pins 8&7) sends the signal thru C25 (bypassing C27) and into R169, C26 and R168).

The components for ch2 are C32 (30hz), C29 (50hz), R179, C34, and R174 and IC6.

More info: (Links will open in new window)
TI RC4580 Datasheet
Pass Labs
Opamp Intro

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Update 10/22/2013

I have come back and studied some more.  I modeled the above HP filter in CircuitMaker and it appears that it would be pretty straightforward to change the 50 Hz filter to something more appropriate for vented, IB, or LLT sub use.  Changing R168 and R169 to 70k changed the modeled response to somewhere closer to 11-12 Hz.  This is a start.  Time to find time to hit the bench for some soldering time!

If someone out there has already done this, please leave me a note below!

Mike

Dell (Toshiba) Bluetooth 350 and Windows 7- FIXED

5/7/2023

Reports say that it seems to work on Windows 11! Another year, another OS!

1/24/2022

Folks, I am blown away. It been over 10 years since I posted this random bit of info I discovered on a long-gone piece of hardware for an end-of-life OS and I am still getting comments from people able to apply it to today's software. Blown! Away!

Yes, this fix reportedly works on Windows 10 according to the latest comment from a user. I love hearing the success stories!

I wonder about Windows 11? 

8/20/2017

Six years and still getting reports that the fix is still helping others get the most from their hardware! Please keep the comments coming as I love reading the success stories!

8/24/2016

By popular demand, here's a couple of how-to links on editing the registry.

http://pcsupport.about.com/od/registry/ht/open-registry-editor.htm
http://www.techsupportalert.com/content/learn-how-use-windows-registry-editor-regedit-one-easy-lesson.htm
Editing the registry My favorite guide! :-)

And George T. has a provided another link to the  drivers
https://extranet.toshiba-tro.de/en-us/supportquality/bluetoothinfopage/news/downloadtoshiba.aspx

Thanks for the kind works and be sire to read thru the feedback comments below for updated and improved information. I have long since retired the laptop so I can't offer new info or insight, but I love hearing the success stories!

3/1/2016

I am gobsmacked that this site is still getting traffic and still helping people get the most from their bluetooth.  Thank you so much for the updates and feedback on working configurations as you discover them. Please keep the comments coming- they make me happy knowing others are still benefiting!

Mike

Original post below:
For those running Toshiba's bluetooth stack and encountering the infamous 'License has expired' message, I have a workaround that seems to be working.
After downloading version 8.00.12(T) of Toshiba's BT stack (from Toshiba Bluetooth Portal), I began getting this message:

"Bluetooth Manager: Thank your for evaluating the Bluetooth Stack for Windows by Toshiba. The evaluation period has expired. Please obtain a license for this version of Bluetooth Stack for Windows by Toshiba."

I did a little digging and found that this was quite common. Now, my BT adapter from Dell in my Inspiron 9300 is made by Toshiba. I used the last version of the stack without problems. So...I want my BT back.

Simple fix- edit HKEY_CURRENT_USER\Software\Toshiba\BluetoothStack\V1.0\Mng. Add a new DWORD key called TestVersion. Set it equal to 1. Message gone.

This key will probably have to be added to each user account on the computer that need BT functionality.

Alps Touchpad on Dell Inspiron 9300 under Windows 7

Dell doesn't support the I9300 under Windows 7. It runs W7 just fine. After install, go to the Windows Update site and let it download the drivers for the x300 video card from MS. The touchpad driver I found that works with the Alps touchpad is from Sony's website. Look for Alps_Touchpad_Driver_7.107.505.102. This is the file I used: Link

The only problem I had was the 'Tapping Off When Typing' option didn't work. I finally was able to get it working by adding an entry to the registry. The needed key is HKCU\Software\Alps\Apoint\Gesture. Add a new DWORD entry called "PalmCheck" (no quotes) and set the value equal to 1. That seemed to do the trick!

Thanks to this posting and user peteostro's postings for help. Link