Google Search  |  Meridian Systems  |  Meridian Streaming  |  Restaurant  |  WiKi  |  Duncan's Meridian Info  |  Board Rules  |  Restaurant Rules
Page 3 of 8 < 1 2 3 4 5 6 7 8 >
Topic Options
Rate This Topic
#161851 - 2012-03-01 17:09 Re: DSP life expectancy ***** [Re: Fiddler]
Registered: 2006-10-27
Posts: 142
Stuart Offline
Hitchhiker
Stuart Offline
Hitchhiker

Registered: 2006-10-27
Posts: 142
Loc: SF Bay Area, CA, USA
Originally Posted By: George Mills
Originally Posted By: Marcus
George, you must live in an enormous domicile!

Hmmm, I had to look that one up. Still not sure what you meant smile



Big house, George, big house!
Actually I thought maybe you'd secretly reformatted your G68 to produce 12 discreet channels!!!
S.


861v6, HD621, DSP5200, DSP5500HC, DSP33, ROKU3, Transporter, VP50Pro, Pioneer 6010, Pronto TSU/RFX9600.
Top
#161858 - 2012-03-02 01:58 Re: DSP life expectancy [Re: Stuart]
Registered: 2006-06-23
Posts: 1,689
Mark_H Offline
Knows where his towel is
Mark_H Offline
Knows where his towel is

Registered: 2006-06-23
Posts: 1,689
Loc: South West, UK
Speaker failure is a nightmare scenario for me as I don't think I can physically remove them from behind my screen without some major (and very careful) manoeuvring. I have 7 x 5500 in my room, with the ones behind the screen bought in 1999. So far only tweeters have failed and they were simple enough to replace. It's heartening to read that not only are they made to last, but that if things do go wrong with the electronics then it's easy enough to pull the guts out for repair. Still, I'm hoping they just keep running... smile


Top
#162157 - 2012-03-07 07:27 Re: DSP life expectancy [Re: Mark_H]
Registered: 2011-08-22
Posts: 1,646
Not'arf Offline
Working on the ultimate question
Not'arf Offline
Working on the ultimate question

Registered: 2011-08-22
Posts: 1,646
Loc: Abruzzo, Italy
Quote:
2 at work (listening right now actually, fiddle music of course)
2 in fiddle practice room (2-3 hours every evening google Amazing Slow Downer)
2 in vacation home (also used for fiddle practice)

Fidler; you could sell your 10 DSP5000s and treat yourself to a new fiddle!!


Audio: MC200, G61R SL, HD621, DSP5500, 5500HC, DSP3100. Subs: 2 x REL Gibraltar 2.
Video: JVC X70, Black Diamond Zero Edge screen 129"(2.35).

Meridian owner since 1998
Top
#223210 - 2014-10-30 16:12 Re: DSP life expectancy [Re: SupreM]
Registered: 2011-02-17
Posts: 1,796
MB Offline
Knows where his towel is
MB Offline
Knows where his towel is

Registered: 2011-02-17
Posts: 1,796
Loc: Winchester, Hampshire, UK
Excuse me for digging this up from the past, but just couple of points in the interests of future readers, it being a wiki entry.

In the wiki, it says two 680 ohm resistors but looking at an earlier 5k amp board, it looks like there's one 680 ohm and one 330 ohm.

The replacement suggested in the wiki is a "typical" resistor, whereas earlier 5ks has wire wound ceramic types. A smiley face 5k seems to have a "typical" resistor but it doesn't look like 680 to my untrained eye. The ceramic is 4W and suggested replacement looks like 2.

Any comments from the EEs out there (apart from get an expert to do it...)?





Bits and pieces
Edited by Tintin; 2014-10-30 19:28.
Top
#252076 - 2016-07-20 07:11 Re: DSP life expectancy [Re: MB]
Registered: 2012-05-01
Posts: 83
RobinASU Offline
Mostly harmless
RobinASU Offline
Mostly harmless

Registered: 2012-05-01
Posts: 83
Loc: San Francisco, California, USA
Was the 330ohm used in front of the negative regulator?

In my M60's (different PCB layout) the drop across resistor R9 is about 33V. The drop across R1, which feeds the positive regulator is about 21V. R9 gets pretty damn hot, and my three M60's had overheated R9 resistors (crispy!) and burnt PCB spots under R9. Around R1 gets warm, but not like R9.

I suspect your 330ohm resistor was used in later models using similar regulator circuits to my M60's to adjust the voltage divider created by R9 and the rest of the negative regulated circuit. The 330ohm resistor seems to shift more volt drop to the regulator and the rest of the negative regulated circuit.

Apparently, the regulators and/or the rest of both regulated circuits have different impedances that were not correctly accounted for. Using 680ohms for both R1 and R9 makes R9 run very hot.

Top
#265046 - 2017-06-07 08:45 Re: DSP life expectancy [Re: RobinASU]
Registered: 2008-10-11
Posts: 487
Tarik Offline
Paranoid android
Tarik Offline
Paranoid android

Registered: 2008-10-11
Posts: 487
Loc: Gloucestershire, UK
Just about to embark on preventative maintenance of the resistors.

According to the schematics, R1 is in front of the +ve regulator and R9 the -ve regulator.

The schematics have also been updated by being written on to show R1 as 330R and R9 as 680R as per the first picture in TinTin's post.

I currently have both R1 and R9 as 680R, should I change to be as per the schematics?


Lounge: DSP5200, 518
Snug: DSP33 x 5, 518, C61R
Office: M33

Top
#265472 - 2017-06-26 20:11 Re: DSP life expectancy [Re: Tarik]
Registered: 2005-09-10
Posts: 346
Steve M Offline
Hitchhiker
Steve M Offline
Hitchhiker

Registered: 2005-09-10
Posts: 346
Loc: South Australia
Is anyone able to answer the question in the previous post ?


#1: 8000s, 5500HC, 8000s, 861v8, 800Dv4, HD621
#2: 6000s, 6000C, 5000s, 6000s, 568.2mm, 598DP, 511
#3: 5500s, 5000C, 5000s, 561, 800v3, 518
Top
#265473 - 2017-06-26 21:11 Re: DSP life expectancy [Re: Steve M]
Registered: 2008-10-11
Posts: 487
Tarik Offline
Paranoid android
Tarik Offline
Paranoid android

Registered: 2008-10-11
Posts: 487
Loc: Gloucestershire, UK
I didn't want to risk making an expensive mistake so I replaced like for like.

When I opened them up I had two 680 ohm resistors (R1 and R9) so put the same back in, however I did increase the rating to 5W.

As the speakers were manufactured in 1994 (I think), I would be happy if the resistors lasted another 23 years.

Both of the resistors in both of the speakers were crumbling so I would recommend everyone with a speaker of similar age to at least check the resistors. You may save a larger repair bill if you catch them before they fail.


Lounge: DSP5200, 518
Snug: DSP33 x 5, 518, C61R
Office: M33

Top
#265504 - 2017-06-27 22:47 Re: DSP life expectancy [Re: Tarik]
Registered: 2005-09-10
Posts: 346
Steve M Offline
Hitchhiker
Steve M Offline
Hitchhiker

Registered: 2005-09-10
Posts: 346
Loc: South Australia
Tarik, thanks for the informative reply. Much appreciated.


#1: 8000s, 5500HC, 8000s, 861v8, 800Dv4, HD621
#2: 6000s, 6000C, 5000s, 6000s, 568.2mm, 598DP, 511
#3: 5500s, 5000C, 5000s, 561, 800v3, 518
Top
#267787 - 2017-09-14 08:13 Re: DSP life expectancy [Re: Tarik]
Registered: 2012-05-01
Posts: 83
RobinASU Offline
Mostly harmless
RobinASU Offline
Mostly harmless

Registered: 2012-05-01
Posts: 83
Loc: San Francisco, California, USA
Originally Posted By Tarik
I didn't want to risk making an expensive mistake so I replaced like for like.

When I opened them up I had two 680 ohm resistors (R1 and R9) so put the same back in, however I did increase the rating to 5W.

As the speakers were manufactured in 1994 (I think), I would be happy if the resistors lasted another 23 years.

Both of the resistors in both of the speakers were crumbling so I would recommend everyone with a speaker of similar age to at least check the resistors. You may save a larger repair bill if you catch them before they fail.


I just checked and I did change R9 to 330ohms so it runs cooler. This shifts some power to the regulator, which is not a big deal since it's bolted to a large pad. Just in case I glued small heat sinks to the regulators and R1 and R9. I changed all electros to Panasonic FRs, except electros in the signal path, which I changed to a higher end film type that I can't remember. There was an improvement in sound, which makes sense. A lot of the removed caps were obviously brown (especially around R9) and tested to only a fraction of their rated capacity.

Sounds like you are all good to go! Nice work on the DIY recap.

Edited by RobinASU; 2017-09-15 05:39.
Top
#267958 - 2017-09-22 21:55 Re: DSP life expectancy [Re: RobinASU]
Registered: 2000-05-28
Posts: 8,672
Fiddler Offline
President of the Imperial Galactic Government
Fiddler Offline
President of the Imperial Galactic Government

Registered: 2000-05-28
Posts: 8,672
Loc: Northeastern, USA
I was swapping "Cabinets" with a friend (rose for cherry) and inspected the infamous resistors and they were cooked on both 24/96 sets (all 4 24/96 backs).

2 were "Smiley" 300xxx S/N neither ceramic. Assuming 2 680's (cooked)
2 were "7 Segment" 200XXX S/N neither ceramic. Assuming 2 680's (cooked)

I also recently bought another smiley pair and inspected one of them and took pictures for reference and they looked great.

1 "Smiley" 300xxx S/N 1 is a 330 Ceramic the other not Ceramic.

I also have another ancient 18bit pair and those look great also (only one). 100xxx S/N both non ceramic. They are both 680's.

So we were trying to figure what is the best resistors to use. He is a very experienced EE guy. Between us we have about 16 DSP5000's and we plan to do this maintenance to most of them.

For grins I pulled up the photo of most recent pair that looked good and noticed that in ADDITION to the 330 Ceramic. There is another Mod that was done in that area. Take a look at the photo below.

There was mention of schematics (old and new). Could someone PM/Email me those schematics.

Also just lowering the 680 to 330 could RAISE the heat the resistor has to dissipate not lower it.

The 330 might need the rest of the mod.

I'll check exact serial numbers to double check what is newer than what.

Also this voltage regulation does NOT feed the digital board.



- Fiddler (IMHO)

If you think listening to music is fun, try learning an instrument.
HT: G61RSL, 4x5K, 5.5KHC, 2xSC6000, Transporter, HD621, Philips BDP7501 4K, Tivo, 65" LG OLED 4K C6
Computer: Foobar2000, 5K, Mojo, HiFiMan HE1000 V2
Top
#267961 - 2017-09-22 22:28 Re: DSP life expectancy [Re: Fiddler]
Registered: 2012-05-01
Posts: 83
RobinASU Offline
Mostly harmless
RobinASU Offline
Mostly harmless

Registered: 2012-05-01
Posts: 83
Loc: San Francisco, California, USA
You have a lot of work ahead of you!

On my M60s the overheated resistors from the power rails to the regulator power input create a voltage divider with the regulator and dissipate some of the power the regulator would normally take.

The regulator pulls constant current to feed the connected circuit, so when you reduce the value of those resistors the power dissipated by them is reduced and added to the regulator.

On all three of my M60s the negative regulators had a lower drop across them than the positive regulators. They are different parts. Lowering the value to 330ohms shifted power to the negative regulator.

My PCBs were toasted and I didn’t want that to deal with resurrecting them again. I recommend replacing with the same value you have at a higher power rating. It will still get too hot, but should last at least another 10 years assuming your PCB is in good shape.

If not good shape, you might want to consider 330ohms. Obviously, you should check voltages before and after and understand what you are doing before you do it. These were all hand made boards and there seems to be some variation in design and parts used, but they seem similar.

-R

Top
Page 3 of 8 < 1 2 3 4 5 6 7 8 >

Moderator:  Carl, Duncs, ncpl 
Who's Online
3 registered (Jeje, Mr Meridian, Syles), 73 Guests and 2 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
Don1976, StevieB, DennisTheMenace, K13, Peter George
4788 Registered Users
Top Posters (30 Days)
CMB Integrations - Bruce 29
Gianni 22
Mr Meridian 20
Ian 19
AudioImages - Rick 19
Top Posters
VirusKiller 12595
Fiddler 8672
ncpl 8542
Carl 7963
Ian 7833
Forum Stats
4,788 Registered Members
18 Forums
26,636 Topics
266,680 Posts

Most users ever online: 523 @ 2019-10-22 09:23
Meridian  |  Media Centre  |  Support  |  Firmware Release Notes  |  RSS Systems  |  RSS Streaming  |  RSS Restaurant