Orban Optimod 8100A Repair

[@pileofstuff]

Oh wow, I haven't seen one of these in probably 30 years. Thanks for the nostalgia

[@AERVBlog]

Your welcome. Sometimes my nostalgia is still in service.

[@SpeakerFreak95]

I love these boxes. A stock 8100 with some mods, Texar prisms and a Compellor make up my little LPFM air chain. Least fatiguing station on the air in my area!

[@AERVBlog]

Sounds like what we had for while. I would use it if I owned an FM but I am not one to fight the loudness wars.

[@stopthebus]

@@AERVBlog The loudness wars went out with the 90s (but try telling some of today's stations that!) I engineer for quality, not loudness. If a station asks me to "turn it up so we're louder than the next guy" I tell them to find another engineer.

[@stopthebus]

This line up was a killer back then and it still holds its own today. Give me quality over loudness any day! I still have a number of stations running the 8100A/1.

[@AERVBlog]

@@stopthebus I agree mostly but I am 70 and I like clean clear sound that I can understand the words in the song. Most songs today it doesn't matter much since the material you get is already compressed and expanded so much that the wave form looks like square waves of varying duty cycle all slammed up against the top and bottom rails. It is a disgusting sound when you get it. Just my opinion.

[@stopthebus]

@@AERVBlog That's why I don't listen to today's music. Poorly mastered and engineered by people who have no clues on digital equipment that is very unforgiving at high levels. Can't beat some well recorded 70s or 80s music through an 8100A set for quality, not loudness.

[@SFDJMark]

The DB25 accessory port is for the "XT" (or "XT2") 6-band limiter add-on. That box functionally replaced the 8100'a high-frequency limiter. I believe the test jacks could either output processed/pre-emphasized audio, or feed audio directly into the stereo generator.

[@AERVBlog]

Thanks. I later found that out about the connector. The jacks on the back do indeed have pre-emphasized audio. I just repaired one for a client that wanted to use it for studio purposes and wanted an output that was not pre-emphasized. I put a 7500 ohm/.01uf cap on those outputs and that did it. Flat as a barn door 20-10k without making the whole unit non-servicable for what it was intended.

[@AERVBlog]

Found that out later. Thanks for watching

[@db2248]

Hi: That power supply regulator was an aftermarket improved version designed, built and installed by Bill Sacks (SK) and his wife Kim.

[@AERVBlog]

I don't know why I don't get all my comments emailed to me. Sorry for the delay. I found that out. It just took me a while. Pretty good regulator. Much better than the thing that came with it.

[@db2248]

Would enjoy seeing the schematic of the PS. Wonder why it is better?

[@AERVBlog]

@@db2248 better regulation and cleaner from what I can tell.

[@bradleysmith681]

Yes, unfortunately Bill passed away. Big loss for the broadcasting community..

[@AERVBlog]

@@bradleysmith681 yes it is.

[@fabiotvcaju]

Hello, I would like to ask a question. I'm from Brazil and my orban is an 8100a/xt2 it has a small distortion in the highs what can I do to correct it. this does not happen in all songs, only in some. which components do i have to change or adjust and where do i have to do it

[@AERVBlog]

That is a very hard question to answer without having the unit on the bench since it could be a lot of things but I would suggest you do a full recap. It is not a terrible job and it should be done anyway. Thanks for watching.

[@sp1068]

I have one of these now. Audio seems to smash and lisp very easily even at 30% on the meter. Would assume it needs caps, and I don't believe it's had any power supply updates. don't think mine has that rear board. Wonder what symptoms arise from the supply not being updated to that latest revision?

[@AERVBlog]

I think you are right. It probably needs re-capped on at least boards 6 and 7, I think. As far as the power supply goes if the + and - 15V are not right or low you won't have any headroom so that could cause your kind of problems too.

[@sp1068]

@@AERVBlog That's good info. Thank you

[@davidv1289]

Nice repair! The gap in the wire of that choke coil seems to indicate that a large surge occurred - lightning or connection to a voltage source. Did you notice any flash marks on the circuit board or cover? "Big , Heavy and Built Like a Tank" - my favorite type of gear - I'm currently repairing an HP 8642B Synthesized Sweep Signal Generator that weighs in at 71.5 pounds! A really beautiful piece of test equipment.

[@AERVBlog]

I did not find any signs of lightning or surge. Very confusing. The old stuff is usually best but not always. I would rather have a good modern scope than either of my boat anchors but they are still very useful. Thanks for watching.

[@DalmaTon-Records]

Was that the inductor wrapped around the resistor forming an R-L filter? *Cheers!*

[@AERVBlog]

Where in the video are you talking about?

[@DalmaTon-Records]

@@AERVBlog That thing you repaired which had one wire end of that inductor cutted, like at 32:45... Is that an inductor wrapped around resistor with its ends soldered at the end of the resistor, or inductor only? There are some low and high pass filters done using this kind of R-L filters, etc... Btw; very nice video, Cheers!

[@AERVBlog]

@@DalmaTon-Records no. Not a resistor. Just a ferrite rod with a wire choke wrapped around it.

[@DalmaTon-Records]

@@AERVBlogOh, ok. So an ordinary choke. That has a lot more sense anyway than R-L filter here... Thank You for the answer, appreciate it. *Cheers and all the best!*

[@felixhumberto2017]

Great video, I like it, Do you may know how to make the output Composite to stereo? I know the left and right channels come out of the composite connector to the transmitter but i would like to make the composite output stereo, The RCA's are stereo but is not the same quality. Any help? Thank you Felix

[@AERVBlog]

If you are feeding L and R into the Optimod then the composite output will contain all the information necessary to broadcast stereo. Here is a good paper by BE that explains it better than I can. worldradiohistory.com/Archive-Catalogs/Broadcast%20Electronics/BE-The-Composite-Signal-Key-to-Quality-FM.pdf

[@TheDefpom]

Nice repair, I bet that took quite a bit of time

[@AERVBlog]

The initial repair was in real time. There was quite a bit of probe poking and head scratching to figure out the rest. Thank goodness the customer found the Card 0 install instructions. It would have taken a lot longer without it. Thanks for watching.

[@mavic6155]

@@AERVBlog Do you know that all Orban manuals are online for free on Orban's website?

[@AERVBlog]

@@mavic6155 yes. I found that out. Thanks.

[@Justplast]

Love it

[@AERVBlog]

Thank you.

[@bradleysmith681]

Good fix..

[@AERVBlog]

Thanks

[@doctortono]

Dear AERBlog, i have one Orban Optimod 8100A without its internal Board 5 and Board 7, Do you have these boards for sell it to me please?. Contact to me please!

[@AERVBlog]

You might be in luck. Let me look. I have a TV version of that and I need to see if the #5 card is the same.

[@doctortono]

@@AERVBlog thanks for your response!...I will appreciate your help a lot in order to get these Two(2) Boards, #5 and #7. I will be pening! Thanks again!

[@AERVBlog]

@@doctortono contact me at [e-mail] please

[@doctortono]

@@AERVBlog ok, here I go then!

[@doctortono]

@@AERVBlog I sent a email already, please check your email. Thanks