Yaesu 5100 microphone
I have an old Yaesu FT-5100 with a bad hand mic. Does Heil carry a replacement and if not what components are necessary to repair it?
There are five stock hand mics for the FT-5100:
1 MH-26D8 Hand Microphone w/1750 Hz Burst Button
2 MH-26E8 Hand Speaker/Mic w/1750 Hz Burst Button
3 MH-26F8 Hand Microphone w/DTMF Keypad
4 MH-27A8J Hand Microphone w/DTMF Keypad
5 MH-15D8 Hand Microphone w/DTMF Memory Keypad
Which microphone do you have?
The following are connections to the FT-5100 mic connector pins:
1 Up freq
3 Down freq
4 Speaker (if applicable), otherwise N/C
7 E (mic return/ground)
8 Mic output
When you say that you have a bad hand mic, what do you mean? Does the frequency up/down function work? If you have the MH-26E8 version, does the speaker work? Does the PTT switch function, as best you can determine? Have you measured the output of pin 2 to see if there is 5V present? If there is a band changing capability on your hand mic, does it function properly?
I suspect that by “bad” mic, you mean that there is no audio when keyed, but that everything else works appropriately. If so, I suspect the microphone element. With the correct microphone model number, the service manual could be located and microphone element part number could be determined. It's also possible that all these mics have the same mic element part number.
Good luck and 73,
The Yaesu FT-5100 is a discontinued radio.
I have an old Yaesu FT-5100 with a bad hand mic.
What components are necessary to repair it?
A majority of the Yaesu accessories for this radio have also been discontinued.
Your local amatuer radio dealer / retailer will have (or can order) a suitable replacement microphone
from Yaesu, Heil or other third-party supplier.
You have to perform electronics troubleshooting (DIY skills) to answer your question (which part is bad).
You can contact Yaesu USA for the specialized parts (plastic moldings, etc.), IF the micropone is current production or parts are still available.
Common electronics parts can be found at Mouser, DigiKey, Allied, Newark and other commercial/industrial electronics distirbutors and retailers.
These these parts are NOT mfg. or warehoused in the USA,
they must be ordered from Vertex's warehouse in Japan OR from the OEM suppliers in Eastern Asia.
Yaesu Customer Service contact web page:
Vertex Standard (Yaesu) USA
Attn: Amateur Repair
10900 Walker Street
Cypress, CA 90630
For Technical Support or Customer Service call, +1 (714) 827-7600 between 8 AM – 5 PM PST
For Parts Department call +1 (714) 827-7600 (8 AM – 5 PM PST)
Yaesu USA Customer Service, e-mail: firstname.lastname@example.org.
Last edited by W9GB; 02-12-2011 at 07:36 PM.
Nullius in verba
if the mic has low or no audio , those mics had a problem with the coupling electrolytic caps opening up. they used 50 volt caps and in use they only see a very small voltage so they go bad from lack of exorcise heh inside the mic you will see 2 circuit boards sandwiched together, seperate the boards and replace the 2 problem caps is the short version. there is one for the mic audio and one for the touch tone pad. use 6 or 12 volt caps instead of the 50 volt units . N4NLQ has a write up about the problem somewhere out there, find his write up and see if its the same mic you have. I brought 2 mics back from the dead with that procedure.
good luck and 73
Allan, N4NLQ posted a December 2007 response in an Eham.net review of the MH-27 .
This is not so much a review as it is a response to the report of low transmit audio.
Thismicropone is a little small for my liking and feels a bit fragile.
However, I've owned 5 of them since the early 1990's and have yet to physically break one.
Remember I'm the guy who asked the salesman at the cell phone store if he had anything larger!!
The low audio problem is caused by the use of 50 volt electrolytic capacitors to couple both the Touch Tone and mic audio into the line.
The 5 volts in the mic just isn't enough to keep them "formed" and they gradually go open.
I have a narrative repair procedure and scanned schematic put together from the suggestions and contributions of several Hams here on eHam.
I have successfully repaired mine.
eMail and I'll be happy to share. Allan - N4NLQ
Nullius in verba