Removing Ribbon Cable / Audio Reciever - Page 1
Forum section: electronics / beginners

author: dteck
author_rank: Contributor
timestamp: June 23, 2015, 06:32:40 am
content: So I've got an Onkyo HT-R390 that has been giving me some problems. Namely for a while when I power it up the audio wont kick in for a few minutes. Annoying and indicative a problem sure but whateverit worked after that "warm up" period. Well today it is now cutting the audio out randomly and kicking it back on randomly. I'm using the Optical input for all my audio. But when it cuts out even the AM/FM tuners fail to give me any sound. I thought maybe the relays for the speakers weren't engaging but even the headphone jack failed to deliver audio. So it was time to google around and see if anyone had some info. No luck on this model (there were some issues with other models and BGA parts). I did find a service manual. So it was time to pop it open and take a look.Problem is the HDMI input board on top has a couple ribbon cables on each side and normally there is a pull tab for locking/releasing. maybe I'm just blind but I'm having a hard time seeing how to pop these out. Does anyone have any insight on how to go about getting these open?Also if anyone has a suggestion on what might be causing my audio drop in/out issues I'm all ears.

author: Shock
author_rank: Super Contributor
timestamp: June 23, 2015, 07:10:10 am
content: They should just pull out, but careful they can be fragile. Don't make the mistake of yanking on it if the cable is the soldered through ones with plastic support, you can tell by checking the thickness of the pins on the other side of the pcb.Isolate the problem 100% to the amp. Inspect everything on the PCB first, write down voltage and signal levels and refer to the service manual/schematic. Compare to what you get when the fault is occurring. Perform intermittent fault type testing such as tap testing, heat testing, cold/warm/fully depowered state testing, clean the connectors, then if no joy start on checking all the surface mount caps especially if it's a few years old.Google it as well, these type of problems may be common to the model.

author: dteck
author_rank: Contributor
timestamp: June 23, 2015, 10:36:13 am
content: Quote from: Shock on June 23, 2015, 07:10:10 amYou were right I was just being to gentle with them. I had tried pulling on one but didn't go too hard because I thought there would be a locking mechanism. Just some force and a wiggle or two and they all came out. Now I'm fightingwith the wire to board connectors. I thought they would be easy as they had a very visible lock on them. The sides show a snap and I thought it would just be a matter of pushing in the side locks and pulling the connector out.... Maybe I'm just being too gentle with these as well. But I'm not having much luck pulling the wires off.

author: dteck
author_rank: Contributor
timestamp: June 23, 2015, 10:58:17 am
content: Nevermind. A googling turns up that those wire to board connectors are push down to release.... Its been a long night and my idiot is showingI'm going to bed. thanks for your help Shock. From this point on I'll probably post in the repair section.

author: LDM
author_rank: Contributor
timestamp: June 30, 2015, 02:43:36 pm
content: The "warm board works" syndrome sounds like a bad solder joint. Heat = expansion = contact. Try pushing down on components and you may find one where pushing on it solves the problem. Then it's just a question of finding the guilty pin and reworking it.If it's a BGA you may not be able to fix it yourself.Also reminds me of this

author: dteck
author_rank: Contributor
timestamp: July 01, 2015, 09:33:15 am
content: Quote from: LDM on June 30, 2015, 02:43:36 pmI had seen a bunch of videos about people having problems with different onkyo boards that were fixed by reflowing BGA parts. (there was one with a guy who just set a halogen bulb over the DSP). But in my receiver there doesn't seem to be any BGA parts. All the chips appear to be fine pitch QFP or SOPI will say the Analog devices ADV7623 chip there gets hot very quickly. That might be a problem but all the pins appear to still be connected and unbridged.

author: kolonelkadat
author_rank: Regular Contributor
timestamp: July 02, 2015, 12:41:20 am
content: I had a similar problem with my surround sound, different brand and stuff. Granted, on mine it was just the left channel that would pop in and out. On inspection, one (or some) of the electrolytics had over the years vibrated enough to break the solder connection on one of the pins. I honestly wouldnt have seen it if the glue hadnt let go of it as well.

author: josechow
author_rank: Contributor
timestamp: July 05, 2017, 02:15:49 pm
content: Quote from: dteck on June 23, 2015, 06:32:40 amHi dtek,Did you happen to find a solution?I am having a similar problem with my onkyo receiver. The ADV7623 HDMI selection IC is having heating problems. A couple of months ago, the HDMI picture and sound started cutting in and out randomly, but not often enough for me to worry, then it started doing it almost every 2 minutes. I put a small aluminum U channel on top of it and blew air across the top, solved the problem for a little bit, but still giving problems here and there.I want to replace the ADV7623 (not a BGA), but I am not sure if it is programmed in anyway. I assume the primary TI chip on the same board is what is doing all the major overhead control, but I wanted to know if you had a similar conclusion and repair before I spend $20 on a replacement chip.Thanks!