dmccul2698
Member
Last Activity: 01-17-2025, 11:27 PM
Joined: 04-08-2024
Location: VIOLET, la
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Thank you for your input, STj. A note on the schematic clarified the NM abbreviation. NM stands for Non-Mounted. It's a placeholder for a component needed for the board's construction, testing, etc., but it serves no purpose in the end product and is removed before the unit is sold, as I have been told.
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[FONT=Calibri][FONT=Times New Roman]Hello everyone, sorry for the delay in the follow-up.[/FONT][/FONT]
[FONT=Calibri][FONT=Times New Roman]I was able to obtain a 341A SO8 chip reader and used the AsProgrammer software to create two .bin files of IC651 (EEPROM). Using Guify software, I confirmed there were no differences between the two files. Based on this, I am assuming IC651 is functioning correctly.[/FONT][/FONT]
[FONT=Calibri][FONT=Times New Roman]Next, I connected the unit to power, fingers crossed, and used a D-shell single-channel oscilloscope to test voltages. I observed that...Leave a comment:
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In the first image I posted, the diagram shows IC 641 labeled "NM". I went to look for it and its not there. I am missing something.Leave a comment:
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I'm waiting for the analyzer to come from China. In the meantime, I wanted to check out IC 641. Its got the pads on the top side, I thought it was through the board but it is not! There is nothing on the other side of the board in that place but a bunch of labeling for the chipsets that are on side B....Leave a comment:
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The EEPROM IC 651 takes ROM correction from IC 641. IC 641 is not offered for purchase from Pioneer. You can only source it by purchasing the PCB @ $860. There are more ICs not offered for this unit. Is this a common practice in the industry? IS there a way to source a doner chip?Leave a comment:
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Looking around the web, it seems best to test this problem with a 4-channel o-scope. I don't have one of those. Is there another way?...Leave a comment:
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[URL=filedata/fetch?filedataid=333496][ATTACH=JSON]{"data-align":"none","data-size":"custom","data-tempid":"temp_333496_1712933432028_937","height":"203","width":"313"}[/ATTACH][/URL] hello everyone, the site does not allow r posting the complete manual so here is the clip of the error from the manual....Leave a comment:
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I have taken a magnified image of the resister if helpful, I did not want to waste space if it is not necessary 😊Leave a comment:
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Some measurements. there are some misspellings but I can remember how to spellcheck in paint. I do not know if the lack of continuity is normal. Continuity is seen between( the green side) resister bank R651 and associated pins 94.95,96 and 97 respectively. There is no continuity across R651 to IC601 just resistance of .670k ohms
[ATTACH=JSON]{"data-align":"none","data-size":"custom","height":"433","width":"499","data-attachmentid":3251283}[/ATTACH]...Leave a comment:
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The original problem from the diagnostic output was " No ROM Correction"(misstated earlier and I cannot edit the post)
When /CS asserts "Low" the EEPROM (IC651) accepts correction from ROM (IC641), correct or not?
If I am correct should I investigate interactions between IC651 and IC641?
I don't know which will be helpful but I am going to include some measurements I took last night, all are a learning experience for me. BTW I would be excited to use my o-scope but I am afraid I could damage the unit. Further thoughts on correct usage...Leave a comment:
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Hello everyone, I'm new to electronics and new to posting in forums. I have a broken head unit I am trying to bring back to working order.
thanks muchLeave a comment:
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Ok, Maybe Im not asking the questions properly. Please refer to the image (Fig. 1) Legs 5,6,1 and 2 go through a resister bank labeled R651. I don't understand the # configuration next to the individual resisters.
Leg 5 is Signal in from DSP?
Leg 2 is Signal out to DSP?
why does Leg 2 go to R654 then to VCC (Protection?)
Leg 1 goes to ROMCSB. What is this?
I don't know what legs 7 and 3 contribute to the circuit.
I will start w some continuity cks. please forward your thoughts about any of this....Leave a comment:
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Pioneer DEX-P99rs "No EEProm " diagnostic code.
Hello, My head unit developed strange behaviors so I ran the built-in diagnostic package which returned "No EEProm". The service manual says there is no EEProm connected. I approached Pioneer and they said to swap out the DSP board. All said and good but the DSP board is $860 USD. I am hoping someone can help me
1). Understand the schematic and check the connections between the EEProm and DSP
2). Check the functionality of the EEProm
I don't know if this is the unit's problem but it's a place to start.
I have little to no electronic experience... -
Hello everyone, I am a long-time electronics enthusiast looking for a new hobby. I have watched many YouTube videos and repaired a few items. I hope to gain knowledge of electronics repair the help me fix some pet projects. My second post will be about a fussy Pioneer EEProm. Cheers!Leave a comment:
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