Hey Brian, I was looking at both the 87V and the lesser 177, wondering if I'd really need an 87V. Do either of these let you measure audio voltage and give you a readout in dBv scale? I remember years ago a tech had a Fluke that would read out in dBv when he was working on my console. That seems very useful.
Original 1176LN "F" has low output, no compression. What to look for?
- Thread starter rob61
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Brian Roth
Well-known member
I just checked, and the 177's frequency response spec is only 45 Hz to 500 Hz.
The 87V doesn't have a dBu readout mode....but I merely use my TI calculator to get that value.
20* Log(Voltage/0.775) = dBu
The older Fluke 187 did have direct dBu readout and excellent frequency response. Sadly, Fluke discontinued it at least 5 years ago. I often see them on Ebay, but they command a pretty high price.
Bri
The 87V doesn't have a dBu readout mode....but I merely use my TI calculator to get that value.
20* Log(Voltage/0.775) = dBu
The older Fluke 187 did have direct dBu readout and excellent frequency response. Sadly, Fluke discontinued it at least 5 years ago. I often see them on Ebay, but they command a pretty high price.
Bri
I'll go with the 87V then. While I've got this 1176 apart, I'm going to recap it since its never been done. I find 12 electrolytics, but I noticed Dave Kulka says he replaces 14 on his recap. I was thinking that the only ones you'd replace were the electrolytics. There are two tantalum caps... (which would make it 14). Any reason to replace those? Or should I stay with the 12 electrolytics and stop there?
Yes, CR6 is shorted. I'm going to replace that along with recapping all the electrolytics (which has never been done). Once I've got all the caps and ZD here, I'll pull those and also test r85 since I already have a replacement if needed. Do you think that would cover the bases, or could I still be misisng something?
Oh, is there a benefit to replacing the 2 tantalum caps when I recap it or just do the 12 electrolytics?
Oh, is there a benefit to replacing the 2 tantalum caps when I recap it or just do the 12 electrolytics?
pucho812
Well-known member
The fluke 187 was replaced/discontinued. The fluke 287 is a direct replacement according to fluke but I have yet to see if all the specs line up. I have a 187 that I got years ago. Bar far one of the better investments I ever made.
radardoug
Well-known member
Tantalums are tricky little b*****ds, turn your back and they go short circuit, especially older ones.rob61 said:
You might as well do them too.
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Got the 87V, nice. I was wrong, CR6 is not shorted. I removed it from the circuit and it tested fine. However, C24 is bad. I took that out of circuit, and it reads 0L when I test for capacitance.
I figured I'd recap this unit anyways as its never been done. I'll replace all 12 electrolytics. I'll also check R85 too just to make sure its ok. Hopefully once the electrolytics are replaced, it'll work ok again.
I figured I'd recap this unit anyways as its never been done. I'll replace all 12 electrolytics. I'll also check R85 too just to make sure its ok. Hopefully once the electrolytics are replaced, it'll work ok again.
Brian Roth
Well-known member
I thought that at one point you had measured a short in the vicinity of CR6 and C24, which would explain the lack of -10 V. Is C24 shorted?
Bri
Bri
Replacement caps were mostly Vishay, a few Nichicon. I figured matching Farads, voltage and dimensions would be enough, but did not select "Audio" grade when searching.
A lot of the values when "audio" is selected are radial, but the originals are axial. For those in the audio path, is it better to use the "audio" indicated ones (seems to be Panasonic and Nichicon) and mount radials in place of the original axials, or stay with the Vishay axials (not "audio" rated)?
A lot of the values when "audio" is selected are radial, but the originals are axial. For those in the audio path, is it better to use the "audio" indicated ones (seems to be Panasonic and Nichicon) and mount radials in place of the original axials, or stay with the Vishay axials (not "audio" rated)?
Replacement of C24 solved the -10V issue. Thanks all for your input and help. It is working again.
I am waiting on doing a "recap" since its working. I'd like input/opinions on types of caps to use. When they built these, were there different "grades" of caps like today, with some rated as "audio" caps, and others general or computer? I ordered some, but most were general, so I'm wondering if I should search for "audio" caps. Many audio rated caps seem to be radial, so should I use radial in the axial place, or just use a general axial cap.
Any opinions?
I am waiting on doing a "recap" since its working. I'd like input/opinions on types of caps to use. When they built these, were there different "grades" of caps like today, with some rated as "audio" caps, and others general or computer? I ordered some, but most were general, so I'm wondering if I should search for "audio" caps. Many audio rated caps seem to be radial, so should I use radial in the axial place, or just use a general axial cap.
Any opinions?
Seems to be working (compressing). I aligned it according to the procedure in the 1176 manual (link in this thread) exactly as specified.
In 20db GR mode, the meter is zeroed after alignment as expected. But swiching the GR switch to 12, 8, or 4 sends the GR meter higher, even with no signal, or ATTACK fully CCW (clicked off).
Switching to 12, the meter shows +2db in the red, at 8, its at +3db in the red, and switching to 4 sends it over +3. Again this is with no signal or compression. I've aligned it several times. Also, when switching back to 20, the meter takes a long time to return to zero.
Any ideas what to check? Other than that, it seems to be working ok with the new capacitors.
In 20db GR mode, the meter is zeroed after alignment as expected. But swiching the GR switch to 12, 8, or 4 sends the GR meter higher, even with no signal, or ATTACK fully CCW (clicked off).
Switching to 12, the meter shows +2db in the red, at 8, its at +3db in the red, and switching to 4 sends it over +3. Again this is with no signal or compression. I've aligned it several times. Also, when switching back to 20, the meter takes a long time to return to zero.
Any ideas what to check? Other than that, it seems to be working ok with the new capacitors.
Brian Roth
Well-known member
Hmmmmm......double check the polarity of C19/20/21. Did you clean off all of the rosin crap with a flux remover after you replaced all of the caps?
Bri
Bri
