Question about dead Pioneer VSX-818V - Page 1
Forum section: electronics / repair

author: synth-dude
author_rank: Contributor
timestamp: January 28, 2016, 05:42:28 am
content: Hi All,I've got a dead Pioneer VSX-818V Receiver, its completely dead, no lights, doesn't do anything.Checking out the power supply (pic and schematic below), it has a standby circuit which provides 5v from a small transformer/rectifier and regulator setup, which works fine, I can read 5v wherever the standby voltage is on all ICs, connectors and boards. The main transformer is switched in via a relay on the power board after its switching transistor receives about 5v from the "relay enable" pin on the main IC. I've applied 5v to the transistor and conform the relay works, and all "normal state" voltages also are ok once the relay kicks in.The problem appears to be the main IC never produces the signal to enable the relay.Checking out the main IC, I can read 5v and the two standby voltage pins, nothing (0v) at Vcc which I assume is expected as its not yet turned on, grounds are OK, nothing at the various clocks and oscillators. Part # PEG467A8 (nothing turns up online).This is where I'm stuck, I assume from here that the IC (PEG467A8) is dead and I'm not going to replace it, but before I trash the whole machine I thought I'd ask if anyone might know of something else I could do here to work out the issue, or maybe this IC is just dead?I also tried tracing the power button down to the main IC and see if I can activate the line and see what happens, but the power button goes in to another IC, the display IC (part# PE5550, which I cant find online), and there isn't any obvious "power on" lines from that IC to the main IC, I suspect maybe its some data being sent because it has a few data lines between them.Thanks for reading this and if you have ideas please comment.I've attached pictures of the various diagrams:1. power-board-annotated.jpg - power relay board with key components identified.2. main-logic-annotated.jpg - Main board showing the main IC that provides "relay enable" 5v to the power relay.3. image4.jpg - Main IC (PEG467A8) schematic.4. image5.jpg - Relay power board schematic.Any help will be greatly appreciated.Thanks,Synth-Dude

author: synth-dude
author_rank: Contributor
timestamp: January 28, 2016, 06:06:15 am
content: Two other things before people may suggest it, there is no DC on the speaker outputs (a common issue with shorted main output transistors) and the Pioneer " master reset" key combinations (Adv Surr. + Standby) does nothing also.One other odd thing that caught my attention, when I triggered the relay manually all voltages activated across the boards but the display didn't come on, the machine was still completely dead, front buttons did nothing, no display, etc even when the main relay was activated.Thanks.

author: cpuerror
author_rank: Regular Contributor
timestamp: January 28, 2016, 01:55:13 pm
content: Crystals do go bad if they are exposed to vibration. The other thing i would investigate is high esr caps causing voltage ripple and preventing the uC from initializing.

author: mzacharias
author_rank: Frequent Contributor
timestamp: January 29, 2016, 03:40:50 pm
content: Reset worth a try.Tune + and Auto surr/direct for over 2 seconds

author: bigbobster
author_rank: Newbie
timestamp: March 03, 2016, 06:06:32 pm
content: Check to primary winding of the main transformer. IIR there is an internal fusible link within the transformer. I fixed one that failed by grafting wires to each side of the link and running it to an external fuse holder. A bit of a delicate job but it saved the Pioneer from the dumpster.

author: poot36
author_rank: Frequent Contributor
timestamp: March 05, 2016, 04:41:03 am
content: If it has a super cap in it to retain settings when it is exposed to a power failure, try leaving it unplugged for at least a hour or more. There may be a voltage monitoring circuit that is preventing the chips from starting up. Check that if there is one. If you do not have a scope for checking the ripple on the 5V standby line switch your multimeter to AC volts and see what it reads. If the reading is greater then a few volts the meter can not be used for this test. If it reads 200mV or below the ripple is most likely acceptable.

author: Agent24
author_rank: Regular Contributor
timestamp: March 06, 2016, 12:51:33 am
content: Are you sure you get no +5v on Pin 99? Pin 99, 98, 16 and 62 are on the same +5v rail. If you get power to pins 16 and 62, you should be getting power to Pins 99 and 98 as well unless there is a break in the PCB or something.Do you get anything on IC9001 pin 17? This is ACIN(WAKEUP) pin. Driven with AC_WP signal (made from AC WUP from standby board).I'm guessing if that isn't working, it could be another reason why the CPU doesn't run.I think it should be about 5v.You should probably also check Pin 12 (XRESET) to make sure the CPU is not being held in a reset state.

author: Vzwguyjay
author_rank: Newbie
timestamp: August 20, 2017, 07:46:57 pm
content: In the words of Dr Frankenstein "it's alive" thank you very much forums such as this are awesome thank you.

author: mzacharias
author_rank: Frequent Contributor
timestamp: August 23, 2017, 11:44:06 pm
content: So what was the fix? Reset?