UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Midland 77-805 Portapak transmit issue

Damo666 · 2nd Oct 2019, 10:29 pm

The symptom mentioned happens when using 10 x Panasonic NiMh AA Eneloops or 8 x AA Alkaline AA cells with 2 dummy cells = 12V.

The Eneloops are in real good shape as I use these in an high power flashlight which draws a lot of current. The AA Alkaline cells as per the image shown are fresh, too, so it's not a power/voltage sag issue.

I don't have an SLA or Lead Acid 12v battery.

I've connected 12VDC to the jack in the rear of the rig were the battery jack goes using my 30 Amp PSU set to 12V, and the symptoms are the same - but it sometimes works dependant upon where the rig is placed; The lead to the PSU is circa 9ft long, and if placed at the other end of the room with the cable straight, it rarely transmits, but when the lead is bunched together and close to the PSU it transmits fine.

I've attached a couple of images showing the battery pack with the jack lead (black lead) that plugs into the socket at the rear of the rig.

2nd Oct 2019, 10:29 pm	#8
Damo666 Hexode Join Date: Jan 2010 Location: Blackburn, Lancashire, UK. Posts: 399	Re: Midland 77-805 Portapak transmit issue The symptom mentioned happens when using 10 x Panasonic NiMh AA Eneloops or 8 x AA Alkaline AA cells with 2 dummy cells = 12V. The Eneloops are in real good shape as I use these in an high power flashlight which draws a lot of current. The AA Alkaline cells as per the image shown are fresh, too, so it's not a power/voltage sag issue. I don't have an SLA or Lead Acid 12v battery. I've connected 12VDC to the jack in the rear of the rig were the battery jack goes using my 30 Amp PSU set to 12V, and the symptoms are the same - but it sometimes works dependant upon where the rig is placed; The lead to the PSU is circa 9ft long, and if placed at the other end of the room with the cable straight, it rarely transmits, but when the lead is bunched together and close to the PSU it transmits fine. I've attached a couple of images showing the battery pack with the jack lead (black lead) that plugs into the socket at the rear of the rig. Attached Thumbnails